So we were drawing on the boards tonight and have come up with this
the blue and the yellow are the slots - not the road width
back will be elevated, maybe with a hump-te-do in it, esses on the right will climb up to the bridge and then down before climbing up again after going under the bridge - lanes are pretty much the same length - the board is 4.8mx1.2m (16x4) and the track run is around 19m (62ft)
It is a work in progress not a work of art :) :banana-rock:
DM