Let's see, and in now particular order:
1. installed 1"+ Styrofoam insulation in the basement, which is below our bedroom.
2. added a 3" mattress pillow topper.
3. Replaced many, but not all, of my 921 bulbs with LEDs.
4. added external 110V inlet, for a standalone inside outlet.
5. replaced bedroom vent with a MAXX Fan (variable & directional) with remote control.
6. Added many hooks for convenience in bedroom, bathroom, main cabin.
7. Added internal fan in the refrigerator to improve cooling.
8. Replace whimpy nose cap swoosh decal with bigger, better, theme decal (Bear).
9. Added extra smoke detectors, added soap dispensers.
10. Installed flag holder on top of trailair kingpin.
11. Installed door bar on interior screen door. Also added plexi-glass to the screen door.
I'm thinking I need to do the Oxygenics show head after seeing many folks did that.
Always looking for more ideas.