In my opinion, and my opinion only. I feel that on-road has made me a better off-road racer. Learning how to apex a turn is an art in itself. That relates to both onroad and offroad. And honestly just because the fast guys use a certain setup doesn't mean it's good for your feel. I would say to ask one of the fast guys to check out thier car. Most will obligize and help you out. Take it for a few laps and see what they're setup feels like compared to your truck and make adjustments there.
Honestly.....Like said above. Get you a World GT car with 4cell and try that out. That's a real fun class to run and "learn" from.
Hope I helped out. let me know if you need any other help.