Thinking about real world vehicles versus sliding blocks.
Seems like the differences would be
- softened, non-linear angle of attack at point of contact, like the curve of a sled or circular shape of a tire
- the substantial reduction of friction in direction of desired movement,
- a range of travel of the contact point on the vehicle to create give that will deal with abrupt changes to the surface topography
- energy absorption to remove the force of impact from system and prevent bouncing
The sprung/dampened tire is an obvious example. With treads, I think we have rolling and sprung/dampened wheels but they are surrounded with a tread which provides the contact point. There is a built in angle of attack where the front of the tread belt descends, but it is fixed in direction unlike the steerable wheels on a car.
Maybe a solution would be to use a 4 wheeled vehicle model but fix the direction of the wheels to always foward, increase their friction, and drive them similar to current treads… left || right sides get force applied.