Two possible access routes but both involve Highway 82:
From US HWY 24 between Leadville and Buena Vista, take the State HWY 82 west, around Twin Lakes for 14.5 miles for the turnoff left (south) onto the South Fork Lake Creek road. (FR391)
From Glenwood Springs/Aspen, drive on State HWY 82 through Aspen and continue driving one of Colorado's most thrilling passes to the summit of Independence Pass. Continue over the pass, down the east side and from the final switchback that drops you down to valley level, it's about 4.5 miles to the turnoff for the South Fork Lake Creek road (FR391).
Once you turn onto FR391, drive over the new bridge (placed summer of 2014) that crosses the Lake Fork and perhaps stop to admire the narrow gorge the bridge is built over. Continue driving through private property initially for another 2.7 miles or slightly further to where the road forks left for Sayres Gulch (FR 382). Stay on FR391. The 4WD road up McNasser Gulch will turn off to the right in about an additional .6 mile. Stay on FR391. In another 1.3 mile, you'll come to the turnoff on the right for Peekaboo Gulch. There's a cabin in this vicinity and private property belonging to old mining claims. Do not attempt to camp in this vicinity. In a short distance, you will cross Peekaboo Creek. Just past the creek crossing is another private cabin. Do not attempt to camp anywhere near this location. Our son and a friend were trying to find a camp spot in the dark near the creek several years ago and the owner of the cabin fired warning shots at them.
From where the road turns off for Peekaboo Gulch, it's another 1.2 miles to the trailhead and wilderness boundary. The last several hundred yards may become more difficult and this is where the additional ground clearance will be helpful. Our last drive up this road was 2003. Conditions may have changed and we would not be surprised to find the Forest Service has pushed the road closure spot back further down the drainage.
On the east side of Independence Pass, designated Forest Service campgrounds include Parry Peak and Twin Peaks. There are also numerous primitive sites all along Lake Creek, just off the highway. One of the best is here: N 39° 04' 54.99" W 106° 32' 21.86". This is where a diversion tunnel empties out into the Lake Fork and is just under 2 miles west of the turnoff for the South Fork of Lake Creek.
On the west side of Independence Pass, there are designated Forest Service campgrounds at Difficult Creek, Weller, Lincoln Gulch and Lost Man. There are no good primitive sites, but you may be able to use the trailhead parking area across from the Lost Man CG.
As you drive in on FR391, there are primitive sites you can choose from once you're past the initial area of private property, though in the past, we've observed some efforts by the Forest Service to close some of those primitive spots. It's possible to camp at the trailhead where there are scattered willows and a few other spots before the TH.
From the trailhead, follow the old roadbed/trail into the upper basin. The road starts out close to the creek but gradually gains elevation well above it as you walk up valley. It passes through numerous willows, then some conifers as you get higher. Near 12,200 feet, the road takes a sharp turn to the left and then right again. At this right turn, leave the road and walked across the tundra, crossing the creek, to a small tarn at the foot of a rock glacier coming off UN13,312. A trail leads south up and over a low ridge and then contours SW across the slopes of UN13,312 to a saddle SE of the summit. As it crosses the low ridge, you'll see another unnamed pond about 200 feet below. The same trail intersects the ridge at the saddle at about 12,560 ft. It appears to be a well used game/elk trail. Before this ridge, you could turn up a steep couloir that would shortcut some of the ridge. We emerged on the southeast ridge at about 12,700 ft. Wherever you hit the SE ridge, continue hiking over increasing rocks for the final 600 feet to the summit, encountering no real difficulties anywhere along the route. It took us no more than 3 hours from the trailhead.
From the summit, enjoy an outstanding view into Taylor Park. From here, either return as you came or head on NNW to UN13,090 (unranked) and from there over to Prize BM. More ambitious peakbaggers may want to consider adding UN12,862 (ranked 746) along the ridge to the SSE. It goes at Class 2 with alternating areas of tundra, then embedded rock and sometimes gravel,to the summit.
UN13,384 (Prize Benchmark) is sequenced with UN13,312 (Booby Prize) and Middle Mountain. One-way mileage and elevation gain are measured from the summit of UN13,312. Round-trip mileage and elevation gain assumes completion of the sequence.
From the summit of UN13,312, hike down the rocky north ridge toward 13,090. We passed three rocky obstacles on the left each time and when we came to the 4th, we dropped down some and contoured to the saddle. Most of this section is on rock and tundra mix and some may consider brief sections to be Class 3. From the saddle, to save some effort you can contour across the southwest face of 13,090 toward the saddle between it and Prize BM at about the 12,800 - 12,900 foot level. There is some larger rock to negotiate as you near the saddle. After that, it is a moderately rocky scramble of more than 600 feet to the summit, with brief Class 3 scrambles at times. It struck us when we arrived on this particular summit, that this location is a rather pivotal one. This summit is accessible from three very divergent areas that require long drives from very different directions. It's interesting to study the view in all directions. For another useful description, follow the link below to a report by "Furthermore" on LoJ.
From this summit, our sequence takes you over to Middle Mountain, however, some may want to include UN13,460 before going on to Middle. The report in the LoJ link offers some detail regarding that traverse. We did not include UN13,460 because we had already climbed it from Lincoln Gulch on the west side of that peak.
Middle Mountain is sequenced with UN13,312 (Booby Prize) and UN13,384 (Prize Benchmark). UN13,460 (West) could also be included, but we have not done so in this sequence because we climbed that summit from the Lincoln Gulch side previously. It is a challenging ridge connection between UN13,460 and Middle Mountain. The following route avoids the ridge problems. One-way mileage and elevation gain for Middle Mtn. are measured from the summit of Prize Benchmark. Round-trip mileage and elevation gain assume completion of the sequence.
From the summit of Prize Benchmark, make your way back down the east ridge with some 3rd class scrambles to the saddle and part way up the ridge to unranked 13,090. You can either go directly over that summit or save some unnecessary elevation gain by contouring back across the SW face of 13,090. Hike to the saddle between 13,090 and Booby Prize. A game trail that crosses the saddle leads down and NE into the upper western reaches of the South Fork of Lake Creek.
Once in the basin, it's easy traveling again on grass. Contour across the basin heading around the lower east ridge of UN13,460 on a generally NE course. This will drop you into another high basin with several small tarns at 12,400 ft. This beautiful, pasture-like area is dominated by the spectacular cliffs of a ridge that connects Middle Mtn. with UN 13,460. From this heaven-for-elk pasture, head toward the low point of the southwest ridge of Middle Mtn. It is moderately steep gaining the ridge on mostly grass. Once on the ridge, things become much more rocky. The summit area of Middle Mtn. involves a little scrambling around some rock obstacles and makes an otherwise boring, low 13er, a little more entertaining.
For your descent, some may elect to take a more direct route and head downhill to the NE, hitting the old roadbed/trail not too far south of the trailhead. For our route, we headed straight down from the summit to the southeast. There were several hundred feet of scree descent before getting into more tundra. At about 12,100 feet, there is a bench that we considered following to the north, but we could not see a clear route through the dense willows farther down, so we turned more to the south and connected with a very old road shown on the map that led due south from a mining claim back down into the valley and the main road. It shows on the USGS map as a "jeep trail." This old road will diminish some of the willow-bashing problem though it is overgrown in spots and probably more so now. Once back on the main trail this will leave you with a little over a mile of walking to get back to your vehicle if able to drive to the end of the road.