Yep, those tracks will really look real when rolling over objects or small animals Looking very good btw!
I hope you haven't given up on the opening ramp. If you are worried about warping over time, use a piece of acrylic sheet on the inside. If you scratch up both mating surfaces with 220 grit and use super glue, that panel will never warp. I have done this before. Use .093 thickness. That ramp has to be strong enough to handle a few tons of scrap, so a thick panel would make sense.
I think one of the cut-away books shows a crawler interior, no? ( found one )
Can't wait to see more.......