From the main intersection in Westcliffe of State Highways 69 and 96, head south on SH69 for three miles to a turnoff on the right (west) for CR140, aka: Schoolfield Road. Continue west until you have to turn. Make a 90° left, drive a short distance south, then turn back right (west) again, still on CR140. The road begins to gain elevation through open forest with private homes on a series of five, 90° turns. A short distance after the fifth turn, go right on what is technically CR148 that leads more uphill to a trailhead parking area. The road passes through an open field and makes 4 switchbacks to the TH. For our proposed route that will take in Comanche, Spring and Venable, you will want Trail #1345, which crosses the Rainbow Trail in a short distance.
The Alvarado Campground is located just south of the trailhead parking area. This is a "full-service," national forest CG during peak summer months, however, on the San Isabel National Forest website, there is a notice that the campground is without a water supply on an indefinite basis. Plan accordingly. This is a very nice campground with well-developed sites for both tents and trailers. Most of the sites are spread out enough to afford some privacy. There are plenty of trees. The most current overnight rate is $22. There are vault toilets. Sites may be reserved at Recreation.Gov., but we have had some luck in the past with obtaining a campsite on a first-come, first-served basis. On summer weekends, plan on the campground being full, however.
As for other camping locations, the options are rather limited in this area because of all the private property.