I'm in the camp of "less is more". My wife and I have come to view the trailers not as mini-RVs, but as large and luxurious tents. As a result - there's nothing of consequence inside other than living space and storage.
Cooking and cleaning is all done outside. Keeps the interior of the trailer from getting stunk up or gunked up and allows you to give more space to storage.
Here's what we did with our two project trailers and what they ended up selling for (in the interests of info on resale).
We had a 13' Boler
that we did almost what you're planning. We left the sink in - but the water tanks were gone already when we bought it. We pulled the stove, left the icebox but used it for storage of the portapotty - not food.
I was more concerned with having usable counter space than a kitchen. That was a '72 we ended up selling for $2300.
Next project was a PlayPac. Interior was nasty so I did a total gutting and rebuild. Didn't fit a sink or stove (although there was room for it and I think the couple who bought it put in a sink). Had a standard 110 fridge
and halogen puck lights. That one sold in the fall
(bad time to sell) for $1800 on eBay. (Would have gotten more in the spring if I'd have held onto it).
Current project didn't start as a camping trailer but as an enclosed motorcycle hauler. Gonna rig it as a mini-toy hauler. Plan on much the same gear as the playpac (110 fridge
, 110 lights, but will also have some 12V gear (lights and fans) so I'm not totally dependent on shore-power.
It seems to me that resale is affected by many things, luck and timing (right buyer looking at the right time reasonably near to you) and cleanliness (you won't believe the # of trailers on eBay with pics where the trailers are totally filthy. Well from what you said about the crack pipes - maybe you WOULD believe it!). How the trailer is outfitted will make or break the deal for some, but there's a decent market for people who want the minimalist experience.
I remember the saga of Fredrick's poor Compact! I was shocked it took that long. I can tell you though, if he hadn't been so far away, I'd have been seriously interested in getting it for the planned bike-hauler. I'm guessing there's some strong regional differences in buyer preferences. I hadn't noticed until recently what the situation was as National parks out west - real bare bones stuff, so I can understand the appeal of the totally self-enclosed units. Here (Indiana) pretty much everywhere I want to go has power at every site and conveniently located central flush toilets and showers. Not a lot of motivation to go self-contained at that rate. Certainly not for me anyway.