We've been RVing for over twenty years, or even more if you count trailers. We started small, little tow behind trailers like a Scamp. Too confining for periods of bad weather. I also had a pop up at one time, slept 8 but there was only room for 3 or 4 to stand up. Spent a week in 3 days of rainy weather at the beach with irritable children and a brother-in-law with his bitchy wife. Nope, nope, nope.
For long term stays, comfort is a must, and that means room to move around or even have guests.
Even over twenty years old models like ours are still listing for $55,000.00 or more.
The trick is to find a nicely taken care of older model and get a good price.
I prefer Winnebago. I know, some folks don't like them, but there are several different levels of them. They also own Newmar, Chriscraft, and several trailer and fifth wheel companies. They are the largest manufactures of RVs in the world. But there are others that are well built as well.
I prefer pre 2008 model diesels as they have no DEF requirements. DEF seems to be a problem.
We have an Onan quiet diesel generator. It's fairly cheap to run and although they say quiet, it does make some noise, however with the bedroom in the rear and the genset in the front it's not a bother. We sometimes camp in horse pastures at music festivals and sleep well.
A diesel pusher gives you the advantage of air ride, (now that's a big deal), also a quiet ride up front. It kinda floats along quietly.
Tell you what, there is a forum with around 70,000 members where you can go and ask any question and get many many answers quickly. I've been on it for along time and find it very useful.
It's
https://www.irv2.com/forums
It's free unless you want to contribute. Check it out.