I also added the extra drain gate valve next to the cap....small investment, big difference as we always have a small amount of liquids after traveling.
Also agree with slide toppers, love our trail air pin. I also added that little fan inside the fridge to circulate the air (keeps things colder). I added insulation to the ceiling in my basement, replaced OEM shackles with stronger ones with zerks.
IMO, LT tires instead of the ST tires that came from the manufacturer.
Next rig will have auto-leveling.
Agree with several things previously mentioned.