Do upgrades help the selling price?

You did verify the old propane fridge works before reinstalling I hope. The ARB would probably get you more than a non-working 3-way.

Drawers are gone, old antiquated propane 3-way will soon be installed.

The caulk worked great for a glue. It pulled away some of the plys from the plywood instead of pulling apart at the caulk. It came apart with a hammer easily, yet would have held firm forever if left in place.

To be clear, there is a fridge, it is the ARB, just not mounted.
A newbie RVer will think that an installed propane fridge is the greatest thing ever, but seasoned RVers, especially boondockers, will know that propane fridges are a thing going the way of a dinosaur.

I did all this work thinking I would keep it forever, then things changed.
I still lack the heart or energy to undo it all.

There were no "holes" or any damage whatsoever done to the camper for these mods., inside or out The drawers were installed with tight fitting carpentry and I used caulk to "glue" the frame structure to the inside of the cabinet, so all can be undone with no evidence it was ever there. The solar wires enter where the fridge roof vent was. I did it this way to retain value as if it would ever be a collectible.

ARB fridge, $850, Propane fridge I cant sell it for $400, so I may put it back in and retain a much more valuable fridge.

Thanks, I get from these few replies that mods probably do not add value to the avg buyer.

Depends on what the buyer wants. If they want the upgrades then they will pay for them so they do not have to do the work. If they do not want them then you are loosing out as they will not want to pay. When I sold my NL I had many upgrades that the buyer wanted. BUT I had a trailer customized to the TCer that the buyer could not take as it would not fit in their driveway. It was better for me to drop the price and keep the trailer. I sold the trailer separately later.

List it as is and then if someone comes and says they will give you less as they don't want some things you say okay but I am keeping X,Y & Z. You have nothing to loose.

I found modifications and extras will help sell something over stock if done right but rarely bring in the money for the cost and time you put into them. I've bought and sold some off-road toys over the years. One of the toys had twice more in extras than what the vehicle cost and I restored it to semi stock while selling off or repurposing the extras. Another toy, I kept more of the extras on the vehicle and just waited for the right buyer to come along since I was still using it until it sold and was in no rush for the sale.

Buyers only look for ways to whittle away at the asking price and will not assign value to added options. However, there is a very slight chance the right private party buyer might offer a few extra dollars, but a dealer will not.

List it as is for the price you want. Include details, cost and pics of the upgrades. In the body of the ad state that if you do not want "this item" the unit price will go down X amount. And that removal of the items not wanted will take time.

I like the idea of listing the camper the way it is and offer the old fridge re-installation.
The truth is that you never know how the extra options will play.
In last years new cars offer blind spot assistance and braking assistance.
That is about $3000 option to buy the package.
Will it bring much in resale value? Not, but good used cars with this option sell immediately, when those without can sit for months.

Same thing happens with Motorcycles. People put on LOTS of after market goodies. They don't bring $.10 on resale.

The camper you are selling is old and rare . The perspective buyers will either know what they are looking at or not have a clue . Offer the original parts and fridge with the deal , not installed . You have a limited market .