Nice looking rig!
Yeah, the roof is an area that you want sealed up 100%, water can destroy a good trailer if left to do it's nasty work. The Alladin's roof is approaching the end of it's life but there are a few things you can do to make it serviceable for a couple of years. The ultimate solution would be to replace it, then you know you have a good leak-free covering.
I would pay the price and just replace it. You have an easy roof to do with no roof AC and it should be a short day. Shop around your area for EPDM and also look online. If you have a friend in the roofing trade, now's the time to call in that favor.
Good luck with the Car-pet, looks like a great little mountain climber.