I'm the 2nd owner of a North Trail. There's a small amount of water damage in the front wardrobe. Almost directly above that area the seam between the front cap and roof was damaged by a tree branch.
Absolutely no other signs of water intrusion. When the camping season is close to over for the year I plan on having a leak test done (positive air pressure in the TT). At that point I'll know for sure how leak-tight my unit is.
The only real problem I've had so far was a leak in the shower diverter, which I atribute to the prior owner not winterizing properly.