It is, as Tom says, a unique trailer, in that they just don't exist in this good a condition and more. His comments are all spot on.
I would only add that the list you posted could be further improved by adding dates of replacement for some things, and a bit more dstail. Also, the ALL CAPS styling makes it look a bit too strong. Here is my revised version of it for your contemplation:
* Remodeled and repainted (interior, exterior?)
* stored inside pole building since 19XX
* electric tongue jack and 4 balance leveling jacks
* grey tank added for wash water
* matching awning, fabric replaced in 19XX
* spare tire mounted under vehicle
* wineguard amplified tv antenna / cable hookup
* rear view camera & monitor
* water accumulator tank (??)
* shower converted into storage
* air conditioner
* mattress (front) springwall chiropractic
* gas & electric water heater & refrigerator
* thermostat controlled outlet for electric heater
* water tank gage, battery meter, refrigerator thermometer
* heavy-duty RV extension cords to connect at RV park
* dishes, pots, pans, & silver ware
* microwave oven
* electric heater (details: built in, free standing?)
The only thing that might stop a buyer from just driving up and leaving with it is that your tires are too old to be used safely, and this despite their condition. 3-5 years is commonly accepted as the maximum age for tires, whether they have been used or not. I would replace them. And tell people you did.
If you then add that the exterior lights all work, and that you have a good umbilical to conncet it up to the tow vehicle with, you have a winner!
So, as for price, I believe that DKB_SATX's comments are correct: you want to be able to haggle a bit. So since you need to buy new tires, assuming you do, I would go out at $7,900 and for the people that contact you and say it's too high, ask them what they have seen around that's in better condition than had it just rolled off the assembly line?
ps: why aren't YOU keeping it yourself?