I imagine the crown is pretty tough. Looking forward to it!
Eventually, are you going to make a base that matches the topography of downtown Austin? I know there are hills, but are they significant enough to create their elevations? I had a thought about it if you're interested (even if you're not
) : since each block is essentially the same size you could leave a cutout space equal to the size and depth of the bases you've made for each block, then use really low tack glue to hold them in place for when you transport it. But you'll also be able to remove them easily without tearing if you need to fix anything.
OR... don't worry about the cutout because the depth of your cardboard bases can act as curb height where the sidewalks are higher than the streets.