The 'back' topmost (Second leg) straightaway is going to be an old iron bridge - with flat area beneath it for diorama and detail, connecting to the third leg. I went through a few designs before I found one I liked.
I'm currently printing this out - and yes, those of you who print, some of these are ROUGH. I had some temperature issues leading to stringing and leaking. Fixed now and the new sections printing are smooth as silk.
This will fit a crash racers track perfectly.
There are top cross-members that will connect the top of the bridge, I just havn't printed them yet.