What say ye, gents ( @timf / @hacim / @greg / @solscud007 / @lunch36 / anyone else interested in this display)?
I’d advocate using what we already have to get the best effect for the least amount of work. This includes road baseplates with 2-6 straight roads and 4 turns to make a closed loop.
If it is possible to get a 10″ x 30″ (32 stud x 96 stud) hill section of the ravine, it can go on squares 4, 5 and 6.
Unless someone else has a bunch of cars, I can throw together standard LEGOLAND racecars like those from the Victory Lap Raceway set : http://alpha.bricklink.com/pages/clone/catalogitem.page?S=6395-1#T=S&O={} and maybe something like that set can serve as our start/finish line.
We can put tires around the perimeter (or not.) If we have fairly big tires to use as a perimeter, we can lay them down individually. I expect that stacked tires would fall over a lot while the display is setup inside that enclosed display.