Ours has sealant also around low point drains also, no problem. The only problem we have had with camper was rain water running down sides of camper into enclosed underbelly. Dealer simply put very small thin bead of clear sealer around small lip at bottom of sides, no more problem. We replaced omni antenna with Jack antenna and added Fantastic fan to vent over bed. Snaked wire for fan from light near vent, works great.
To winterize, bypass for hot water heater behind panel next to toilet, used Velcro on panel to hold in place after removing 4 screws. Already has hose for antifreeze and bypass valves under 2 panels underneath bathroom sink, replaced screws with screw studs found at Home Depot to keep 2 panels in place. Makes it much easier to winterize with no screws to remove.
I secure our 35 gallon empty waste tank to ladder and have had no problems. This is home for tank when not in use, one less thing to load when headed out camping. Bikes are too heavy for ladder, I tried this first and it did not work. Slide battery over to one side and add another empty battery box to hold wheel leveling wedges found at Camper World, saves time when leveling Camper at campground, just back up on 2 wedges to level camper.
Hope these suggestions help and have fun with your new camper.
2012 Toyota Tundra Double cab 5.7L 2wd towing pkg
24' 2014 Surveyor 201RBS