I would certainly not try to add a slide although there are some folks that build their own trailers and bus conversions, going far beyond that. Sorry if you took my post as an answer to yours. It sure wasn't meant that way. Rving sure is all about fun!
But the other mods you talked about I have actually done, worked around, or researched.
Dual pane windows can be installed by Peninsula Glass for about $2500.00 for the average RV. If you saved $10k on the purchase of a used rig . . .
Hehr makes stock inside storm windows for their RV windows. That is what I used for my HH. I got them at the HH factory for right at $500.00. I installed them myself. They required some mods to the window treatments, adding a frame to allow room for them under the blinds, but worked perfectly, and gave me more airspace than thermals would.
I always recommend folks buying new to get thermal windows BTW.
We fulltimed for six years and preferred not to take up space with a washer/dryer. Some swear by them, some at them, but that is personal choice.
Most of the better brands come washer/dryer ready/prepped. Easily added later.
On our first HH we had a booth in the kitchen that we hated. It took up too much room, as well as being uncomfortable. I removed it, weighed it all and salvaged the paneling, and replaced it with a counter I made and covered with top grade formica.
It weiged the same and looked better than stock.
I built in a custom computer area at the LR end, which took up even less space and worked great. Even the folks at the factory liked my design and commented that it looked as good as they could do it.
We don't do shabby. We do superstock, better than new, when we do a project, so used doesn't mean any less impressive, if not more so, than a unit bought new, a year after purchase. In fact, my rigs were in better condition than some that were only a year old. That is a function of maintenance as well as the quality of the original materials and workmanship.
We also recarpeted the LR, and hallway. The Kitchen and the BR got new window treatments, and we removed the sofa replacing it with two leather incliners.
Doing mods that are as major as I have done require that you understand weights and balance, not adding a larger load on one side than was originally designed, and verifying it with before and after weighing of each wheel, in our case, a dual axle fiver. So I weighed each of the four wheels, and the tongue weight to be sure no major changes to handling would occur.
I also do my own maintenance, with the exception of a few things that are cost effective to do at the factory, which we swung by, whether we needed to or not, annually, if for no other reason than to get the wheels serviced and visit our friends there, made from previous trips.
I agree that some things are not cost effective. Buying one that leaked and has a rotted structure or needs a complete new roof is certainly not cost effective. Unless it is a valuable antique, and is being restored for reasons other than daily use. The skill level and desire on the part of the owner to make it his/hers so to speak also count highly in that decision.
If new floats your boat, you'll get no argument from me.
But unless you order a custom unit from the factory to your specs, odds are that the same or close floorplan has been made before. They usually make a lot more than one of each right?
The real downside for many is the long search for the perfect used unit. You can't just walk in and walk out with it. For some, that, and negotiating with a private individual or dealer on a used unit are enough to never buy used. These are good reasons not to buy used for some folks.
For others, that search is actully fun, and the negotiations are part of the fun.
On my first rig I saved more than 50% of the then current book value used, when I bought it in 1997. Nevermind the savings from the new price.
When I was done with it, I had spent a little over 10% more, making my investment secure for the whole life of the rig. That isn't about profit, it is about cash flow for retired military folks like us who don't have the advantage of our old full income.
I used to restore/build hot VWs and Porsches as a stress relieving hobby when we were active duty. It also provided us with cars and trucks that were way beyond our means new, but actually fun to drive as they were unique, after customization/restoration.
While those things were what floated my boat, and all the rest of our toys, it isn't ideal for many folks. And shouldn't be.
Besides, if nobody bought new, the pool of available used units would soon dry up for me no? And if nobody bought used there would be no trade in value for you when you want to buy new again, right?
So we really need each other for our personal preferences to be possible, don't we?