I've been to the Meadow Creek trailhead on 2826, it is a well maintained, dusty gravel road. There are a few places to pull off the road and camp between Spotted Bear and Meadow Creek, and probably more along 549, but everything past Meadow Creek is in a burn area and won't have much (if any) shade.
I haven't been up 568 toward the Silvertip trailhead, but I have heard the road is similar. That whole Spotted Bear area gets pretty heavy traffic during hunting season and is quite popular for horse packing and river rafting during the summer.