I tend to reverse on my ramps as if just staying over night I leave the den connected to the tug. In most cases I can then release brake on the tug and the den will roll off early in the morning when leaving. Saves starting tug twice. Noise. I always use chocks if not connected to tug and a stand under Aframe as well as jocky wheel going east west. I have on a odd occassion put them in front and driven forward. All works for me but others might do different.

For me depends on the situation but always chock the other side of the wheel so it doesn't roll off the leveling ramp

If the site slopes down from the road then back onto the ramp. If the site slopes up from the road then come forward onto the ramp. That's the best way for preventing a run away van.

Yep same as truck wheel wedges . On the lower down hill side so your not depending on van brakes . Very hard stoping a runaway van !! Trust me it's happened to cable winches doing gully jumps erecting 133kv cable .. It happens .,