Hey Bryce - so great to meet you and a fellow Washingtonian! Here's some details on customizations I've made since June:
Lighting: Yeah I also swapped out the cabin lights for LED bulbs, much more battery-efficient. I also installed LED strip lighting in the cabin and galley, there's a photo of the lighting in my Gallery, check it out. I got the lighting strips at Costco but I think now they have them at Lowes, or order online. It's cool to change colors to whatever suits you at the moment, and the lights are remote-control:
http://www.sylvania.com/en-us/innovation/videos/Pages/mosaic-flexible-led-strips.aspx Curtains: My sister made me a set of awesome curtains, with pockets sewn into them to store stuff like flashlights, my DVD player, electrical adapters, whatever. Smart thinking on her part!
Hitch: My 2012 Pinecone has a hitch receiver in the back, but when I put my bike rack on it and went for a trip to Hood River, the weight of the bike+rack actually bent down the rear bumper! Fortunately I noticed it before something serious happened. I wonder if this is why they discontinued the rear hitch for your model year (which is 1 year newer). I took the trailer to a local welding shop and had a piece of tubing attached that made the rear hitch rock solid. When I get home tonight I'll post a photo and you can follow the link to my Gallery.
Sound System: Not too complicated: all you need to do is mount some speakers, run speaker wire to the Mini Amp, and plug in your ipod or whatever (laptop, DVD player, etc). Here are the parts I ordered which were not expensive at all...and seem to be holding up fine. One set for the cabin, and one set for the galley.
Mini Amp:
http://www.amazon.com/gp/product/B007TUSXEY/ref=oh_details_o09_s00_i00?ie=UTF8&psc=1Adapter:
http://www.amazon.com/gp/product/B002ISBZ0G/ref=oh_details_o08_s00_i00?ie=UTF8&psc=1Roof Rack: I already have invested hundreds of dollars into a Yakima system for my tow vehicle, so I believe the best solution is going to be the Yakima side-mounted version, but I am still researching. If I can get crossbars that are long enough, I can fabricate some sort of changing room/side tent off of the roof rack, I think:
https://www.yakima.com/shop/rack-systems/permanent-installation/wide-bodyTheater: A crazy idea I had which actually works well is that I purchased a 10x10 canopy cover with a privacy screen on one side. I also purchased a very small hand-held portable LED projector. So, my kids and I have actually had movie night under the canopy off the back of my TD with my laptop hooked into the galley sound system, and projecting the movie onto the privacy screen of the canopy. Add camping junk food and it's fun for everyone!
Electric Blanket: I've camped out in 40-degree weather with zero problems and stayed nice and warm underneath my electric blanket. Worked like a charm.
Well that's all I can think of for now!! Let me know if you have questions! Can you post a photo of your gear hammock??
Greg