On the sleeping, the dinette makes into a full size bed and the couch into a jackknife bed. I would say you could comfortably sleep 4 small kids on the dinette and couch OR 2 adults. The main bed in the front is a Queen. So 4 adults or 2 adults and 4 kids.
The trailer has never had any leaks. Checking and re-caulking the roof is part of normal maintenance and should be done yearly. The roof itself is still original and in great shape since it's been kept in covered storage. Normal maintenance is just touch-up caulking around the vents, antenna, etc so that you don't have any leaks! Same goes for watching the caulk around the windows, doors, speakers, hookups, etc. Clear industrial silicone is what I've used on this trailer to make sure everything stays nice and sealed up.