So far I have:
Memory Foam Mattress pad
Replaced remaining incandescent bulbs with LED (some were already, but not all??)
Second battery
Modified a Weber Q2200 for LP propane
Second LP propane port for my Weber Q
Longer gas hose on the outside cook top, original was just a wee bit too short.
Additional 120V outlets, with USB charging ports, in the kitchen and slide side
Camco screen door cross bar
Progressive Industries EMS-HW30C surge suppressor with remote display
Steadyfast stabilizers
Winegard RV-WING Wingman UHF Booster
FastWay one-step Wheel Chocks
I am sure there will be more to come
-Brian