Our KZ JAG roof ended up like yours. First estimate came in at $8400 and that was assuming no damage in the walls. If they found more damage, it would cost even more to fix. As much as we loved the trailer, hard to justify that much money in a rig worth $9500. IF we fixed it, we would still have a rig worth $9500.
You might go to an RV dealer, ask about the roof and if the estimate is sky high, ask about what they will give you in trade on another unit on their lot. We received $7500 trade on the KZ with dealer knowing the roof wasn't in great shape.
2015 White Hawk 20MRB
2011 F150 Non EcoBoost (5.0)