I think you'd be time and money ahead to start with a Blazer or K30, unless the trails are really tight where you're at. Then I'd have to tube out said Blazer or K30. Or put an S10 cab on it- preferably one of the newer crew cabs, exo'd of course. If a fullsize is out of the question, then a Toyota truck or Runner with a SBC/ TH350/ Toy case(s), and 3/4 or 1 ton axles using the Sky manufacturing SFA kit. Probably with nitrous.