I dont know where you are in Fremont but if you head north to M20 there is a trail head for dirt bikes and quads. Its between Wisner and Gordon. Of course you cannot go on those trails but just east of it on M20 is a dirt road that goes north that will get you out into a decent network of forest service roads that you can take up to Baldwin.
Plenty of camp sites out on those trails once you get north a ways.
Get yourself a MVUM for the Forest Service roads.
If you have a gps check out VVMapping.com