I drove my stock '01/'02 Chevy Roadtrek 190 on quite a few Forest Service dirt roads during the roughly two years I had it. A lot of such roads around here are quite steep, and a few were pretty badly rutted. Being a gear head, I knew quite well where the lowest point under it was (generator exhaust) to avoid dragging it. I only did it in dry weather. Keep in mind that the early Chevy Express Roadtrek has very little ground clearance, even compared to other B's.
In looking for a better mobility in a similar size, I found the Tiger CX. It's a B-sized C. It's much the same size as a small truck camper, at 19' on a standard cab, but has the B/C virtue of cab-to-coach access. More ground clearance & larger tanks than most B's, OEM four wheel drive, and choice of engines, chassis brand, and cab trim level. Definitely short on stealth, tho'.
www.tigervehicles.comJim, "Mo' coffee!"
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory')