From the trailhead parking area, walk across the nice bridge (wish we had enjoyed something like that back when we were climbing the 14ers in the late 70's), and follow the usual path up toward Grays and Torreys. The old roadbed - now trail is actually a part of the Continental Divide Trail now all the way to the summit of Grays Peak. At the top of the second switchback at 11,885 ft., head north following an older, unused roadbed for a short while, then pick a place and just head straight up the side of the peak on almost all tundra, all the way to the summit. At times you may encounter small scree depending on the exact route you take, but there are no major obstacles. Just steer clear of the prominent gully system that divides the east slopes from the north ridge. There's nothing more exciting to report here. We crested out at 70 minutes from leaving the parking lot, but we were booking it.
Take your time at the top taking in the view. Return as you came or consider the following descent route: Begin a descent by hiking along the SSW ridge that connects over to Torreys Peak. That portion of this ridge which is actually on Torrey's is often referred to as the "Kelso Ridge." Don't confuse what you read about that section of ridge with the portion that comes off the summit of Kelso down to the Kelso-Torreys saddle. We did this descent more for interest than anything. The hiking along the ridge is all Class 2 until you come to about 12,590 ft. At that point the ridge becomes rocky and offers a little bit of scrambling. We found a few obstacles along the descent on the ridge proper, but nothing difficult and it made an otherwise boring hike a little more enjoyable. We've seen more than one source report these last 150 feet to the saddle as 3rd class. If it is, there's no threatening exposure. The only reason we can think of for avoiding this last section of ridge would be if you had younger family members along. From the Kelso-Torreys saddle, drop off the ridge on the east side and follow a trail back to the main Grays-Torreys trail. Hike back down to wherever you managed to park. Old-Man-On-the-Mountain makes for a few pictures as do some clumps of columbine and paintbrush back along the road. Also, there's frequently some mountain goats in the vicinity to enjoy and photograph.
Alternate routes: 1. Reverse the descent route and go up the Kelso-Torreys ridge to the summit of Kelso. 2. For far less human activity, head up the old road that leads into Grizzly Gulch. The turnoff for this is about 1.1 mile up the Stevens Gulch road. Hike about 1.5 miles SW up that road and then turnoff to bushwhack SE, then south into the basin below the Kelso-Torreys ridge and saddle. Aim for that saddle, then head up the Kelso ridge NNE to the summit.
Links to other information, routes & trip reports for this peak that may be helpful.