I do not have that model but will shoot a little help.
1) Leave the area near the shower base uncalked, it is left that way to let any water that could possibly get behind the shower stall to flow out and into the shower base. The shower base goes up an inch or two behind the wall and water cannot travel against gravity so it will be fine.
2) Make sure the "fan" is set to auto on your thermostat, if it is set to low or high than it will run, pulling cold air from the outside and into the trailer.
3) never bypass the black tank or any tank for that matter, put 5 gallons of clean water in it, use it til it is full, dump it, clean/flush it, put 5 gallons back in it and repeat. You do not want to allow you tank to be "dry" as it will allow solids to build up in there and never become flushed out. This will eventually cause a build up of "solids" that you do not want to have to deal with. I use the GEO method to help keep things clean and slick.
Hope this helps answer some of your questions. Happy Camping!
2014 Prime Time Lacrosse 329BHT Luxury Lite Touring Edition
2015 Silverado 2500HD DMAX