From US 24 in downtown Leadville, turn east onto East 3rd St. This is closest to the south end of town. US 24 at this point is designated "Harrison Ave," which is just south of the Tabor Opera House. Go a few blocks east on E. 3rd, then turn south onto South Toledo St. which will become County Road 2. In about a tenth of a mile, you'll pass East Monroe St. coming in from the west (right). If you're arriving in Leadville from the south, you could use a right turn onto Monroe as a means of accessing CR 2. The paved CR 2 leads south and southeast up California Gulch, passing by both old and newer mining sites. At 4.4 miles from US 24 (Harrison Ave.) in Leadville, you'll come to an intersection. The right fork leads to an active mining operation (ASARCO). Take the left fork which continues east, staying well above the bottom of Iowa Gulch. This fork is CR 2B which becomes graded gravel. Continue east another 2.3 miles to a small pullout on the right hand side of the road. See trailhead coordinates. Most passenger vehicles should be able to make it to here. The road is in better shape than the San Isabel NF map would indicate. If unable to park here, just a little farther east on the road is a pullout on the north side that can accommodate several vehicles. Going beyond there, we would recommend a higher clearance vehicle.
There are so many old mining claims and active mining operations throughout California and Iowa Gulches, that we cannot recommend any at-large camping. Most anything you would try to camp on would likely be private property. On CR 2, where it crosses the ridge that divides California and Iowa Gulches, there appears to be a track leading west off into the trees from where the road curves back east from going south. Coordinates are: N 39° 13' 38.08" W 106° 15' 02.67".
The closest National Forest Campgrounds are located around Tuquoise Lake west of Leadville. Campgrounds include: May Queen, Silver Dollar, Molly Brown, Printer Boy, Belle of Colorado, Baby Doe, and Father Dyer. Consult your San Isabel national Forest map for more information on these. It may be possible to make reservations for some, but expect them to be full on summer weekends if you're hoping to just get lucky. From any of those campgrounds, you could easily drive to the Iowa Gulch TH for Dyer in a bout a half hour to 45 minutes.