Smile,
Do a forum search on "Sienna" and read not just the Sienna posts but also the posts about towing with a minivan. You can also find posts about towing with 3500lb tow limit crossover SUVs such as the Highlander or Pilot which is similar. People do it but with mixed results. I towed with my lexus rx300 for a while before I traded up to a 5000lb vehicle. With the RX300, my mileage changed from 22-23mpg without to 16mpg with the TM.
At the moment (on my 2720SL) I have a shelf which hinges up on the side of the fridge cabinet and I put my lcd tv on that so it doesn't take up counter space.
I don't find the 3rd party microwave any trouble. I picked one which is lighter in weight than most. It sits on the floor in front of the wardrobe during travel and takes all of 5 secs to unplug and put there ( or vice versa)- a very small addition to the checklist of things to do when setting up camp or and tearing it down.
Trailmanor use sheet vinyl floors ( I replaced ours with vinyl tile but for looks, not wear - vinyl tile is only a little heavier than the sheet stuff). In my mind, wear is not an issue for the comparatively little time we spend in the camper. You can get vinyl tiles these days which mimic hardwood floors pretty well if its the wood look you're after, and they're a lot lighter than laminate.
Here's a link to an example DIY carport site:
http://www.coverquest.com/covers/carports/index.php
They do 7' tall metal carports. My local Lowes also sells something similar and I think may go down to 6 ft high. However, since a closed TM is between 79" and 82" with roof a/c and no lift kit you probably don't want to go lower than 7 ft.
-Paul