It's interesting to see some convergence. These are the drive configurations for our two leading design concepts.
Code:
One Wheel Two Wheel
_ _
| // | || ||
_ _
O O
// = driven and steerable, || driven fixed, | and _ fixed freewheeling.
O = Trailer Hinge Pin
Design CG is over the single driven wheel for one wheel drive
and between the two driven wheels for the 2 wheel drive.
Driven wheels are dropped so that the non-driven wheels
do not normally touch the ground unless external forces are in play.