ok, carnagie has a little crawling course, two mud pits primarily and some river beds to drive through. if you have a quad or dirt bike its great fun to head up into the hills, but no truck up there. oh and they're best known for the mhill climb competitions.
le grange east of modesto is good fun with moderate off-roading. it has a small pond like area to run through w/ 44's and several mud pits w/ loads of ruts right now. they have loads of short hill climbs for trucks and again, lots of fun for quads and dirt bikes.
there a place west of patterson that has all kinds of great mud holes and loads of trails. dirts bikes quads and trucks runs.
holister is about one of the best here in norcal though. rocks, mud, river beds.
for a short trail, ride try strawberry east of stockton, only one kinda rough spot for 33's and a good day ride.
up north of sac there's all kinds of cool river bed runs, by collusa, orville, chico, and i'm sure there is way more than this.
rumor has it that they're even planning an off-road park in waterford, w/ flat oval tracks, mud bogs, rock crawls, and more.
hope this helps
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