I wouldn't panic yet. I think you need to do more to determine where the leak associated with the mattress is coming from. I'm not familiar with your camper, but from googling it, it seems that you don't have soft sides anywhere, so you need to trace the obvious areas that it could have gotten in. Windows, doors, roof etc. My personal thought is if it's a sealant leak, you fix it, learn to check regularly and go on with things. RV roofs are sealed with sealant, which moves and pulls away with age and RV movement. I just had a new roof put on mine (manufacturers defect) and after hauling it 2-3 times, I had to re-seal spots where the sealant is meeting the sides of the camper. Not the dealers/roof installer's fault - just movement and the ways to sealant.
I'd do some research and contact the dealer. Google your trailer and leaks, and see if it's a common leak (for instance, my particular camper is prone to slide leaks - but there is an easy fix...fix and done) and how it's repaired. Ask the dealer what they propose. If you agree, have them proceed. Test it, monitor your sealant, and see what happens.
It certainly is frustrating owning an RV - small things all the time, particularly with new ones and the first time out every season. I'm not far from where you are, and that dealer has a pretty solid reputation in our area - I'd give them a shot.
