How about a whole row of small wheels all along the frame? We're not going to do that, but with enough momentum and 4-wheels driven, it should just sail over the rail. The little wheels in the middle should be 3.5" from the floor for maximum effect. Maybe a two-wheel lead in at the front with two sizes would be more effective than a skid. We might even actually try that. Roller blade wheels as the second wheel maybe?
Just remember, free advice is likely to be worth just what you paid for it.
