EDIT: Scrap what I said, looking at the model, m36aa_01, containing the valley and surrounding rocks, you would need to edit that to add the bridges me thinks. Good news is, it's only one model, and the rest can be left as they are.
Anyway, love the find, please try and do this, it would be brilliant
I reckon what would be quite cool though, for the south ones at least, is to have paths diverging from the path leading to the academy, that way you could maybe see the platform that leads to the tomb from the valley, but you'd have to go searching to actually find the way there, might make it a bit more interesting. You could even have a path leading through the caves, if it isn't too much work