I have your same unit (as you have already spoken with me) and here are the things I have done.
Cannot find water filter ANYWHERE inside trailer- so buy the ones to screw on the hose.
X2 on the permanent progressive surge unit- I mounted mine on the outside of the box that stores the power cord. Works great and easy to install with all the room in the storage area- i put the display on the cabinet/ bunk ladder where I don't think it will be kicked.
LED's are a must- I went with warm white on the inside and used the flat panel type in the bathroom where more light is needed. Also added an additional light in the shower per DW request and the extendable shower rod is a must! Oh yea, get the oxygenics shower head too.
Put a 400w inverter in the entertainment center to power everything when dry camping. LED tv's use less power than LCD's but the bigger the TV, the more power used. With TV, DVD and soundbar and power loss, it runs about 100w which is about 7amps?
TPMS for the tires, Battery cut off switch, led strip for the awning, hard start capacitor for the a/c, replaced the single power outlet for the micro with a dual and using a 2' power cord for an extra outlet in the kitchen.
Built a bumper mounted BBQ rack- BBQ has it's own container for storage.
I think that's it. Sorry to drag this on so long.
2014 Stealth Evo 2850 "Woodstock"
2011 Toyota Tundra Rock Crawler TRD 5.7 "Clifford"