I think you might want to look into doing some easy mods as have been mentioned on the truck to see if that won't calm it down. I had just visited with a neighbor here in the park about 2 weeks ago saying he used to have a problem similar to what you describe and said he made a great improvement by replacing the 5th wheel hitch. I'm sorry but I do not recall the brand he said he bought but said his original had a lot of pushing/pulling, banging etc. That may be of benefit as well.
As far as getting a "nice" class A...I would think about that if I were you. When I retired I was dead set on a "nice" class A; about 429k if I recall and we were getting very serious about it. The problem is the same as you will probably face; that's a lot of "stranded" investment to sit around 6-8 mos. a year. Unlike a trailer where you worry about a few things because it sits idle, that big class A has about a million things that can go wrong, need to be exercised, lubed etc. non stop - driving or not. The drivetrain can't just run out 4-5k miles a year and then be put to bed "until next go round". Nope. For us, the more I thought about it really seriously the more I realized that with something like that you need to be rolling all the time and utilize what you have....we would not have done that. On top of that we would have had to buy something appropriate to tow behind it; everything I own is full size, heavy and just unwarranted in a situation like that.
I will also add that over the last 2-3 years I have talked to 3 folks that use the same storage facility as we do that had nice class As and then showed up with a 5th wheel. I asked them what happened; to a man they all said they were too much trouble. So I would think pretty hard about that change and maybe take the time to mod the truck (maybe trailer) to get it right. It would be terrible to take a bath on the existing trailer, buy that class A, decide it wasn't your cup of tea, sell it and take another, bigger bath. You would be all cleaned, but primarily of cash.
Good luck.
Note; what kind of suspension is on your trailer. I have the MorRyde and swear by it.