I'm more in the "original" camp than some other members, from a cost benefit perspective if the old stuff works or can be purchased used at low prices then replacing it adds cost which comes out of resale.
There is also the question of can you install new or modern amenities with enough skill to provide a good fit and finish that will appeal to a perspective buyer. I might put up with a little "rough" but a functional mod for my own use, but it may put a buyer off.
Last but not least there is what to spend the money on, to most people a light
is a light
, a toilet is a toilet. You put a lot of money into LED lights
and a premium toilet and it may be harder to get that money back. And the mod I think is just the perfect improvement, done well with quality parts just may not matter to some folks.
All that said I looked at the photos Bob posted a link to and I would say he nailed the fit and finish, the camper looks really sharp and would not have to work to convince DW to purchase it. Has to appeal to both if purchased by a couple don't you know. Never having watched TV while camping ourselves (but many do) we might not value that really nice TV set up. But those that do want a TV might pay a premium for having a well done one like Bob has. We read while camping so some of the lights
I think were added would appeal to us. It's a bit of a gamble and takes some thought on where to put your investment if your goal is resale.
If your doing mods with an eye toward keeping the camper that is a FGRV of a different color. Then the cost is measured in the value of your use and enjoyment not resale value. Paint
it pink, gut the inside, cover the walls and floor with shag carpeting and furnish with bean bags if that is what makes YOU happy.