It would take more experience with RVing to answer all the questions you've posed than most people will ever have, IMO. But I've been at it over 30 years now, and owned gas and diesel Class As, and a 5th wheel. So I'll speak from that experience.
Thermoguy wrote:
I would prefer a diesel pusher since I want to be able to tow up to 10K. What should I look for as reliable. Can anyone tell me why I would want a gas Class A vs Diesel pusher?
That one's easy - you wouldn't. Motorhomes are big, heavy vehicles. Consider that there are no over-the-road semi tractor-trailer trucks on the road that are powered with gasoline engines. The reasons are beyond the scope of this post, but they're myriad. Bottom line, diesel is the choice for hauling heavy loads. The sole reason for anyone to choose gas over diesel is price. Test-drive one of each and the imperatives of diesel over gas will become immediately apparent.
I know a Cummins diesel engine should go for 400K plus miles but why are RV’s needing rebuilt with under 100K miles, is it because they site too much and the engines are not designed to sit?
Not my experience, owning 2 diesel rigs over 20+ years, nor have I read about other diesel RV owners who faced premature engine overhauls. If there are accounts out there about this, it's probably because it's always the bad news that gets reported - satisfied owners who never had to do a premature overhaul didn't post about it. I didn't.
I know from looking at trailers, they are built poorly. What about a Class A? Are some built the same as trailers or are they all built on bus chassis?...My wife has her eyes on a Berkshire but being a Forest River product, I am not sure if that is built just like the travel trailers. What advice can anyone give me on this?
The RV industry is like any other; construction quality is all over the place. It's mostly "you pay for what you get" - buy in cheap, and you get cheap, and vice versa. FWIW, "Forest River" is not a brand I'd buy, nor is "Thor".
Looking at the used market, is there any reason to stay away from an older diesel pusher?...I have heard stay away from Thor, is that year specific or anything Thor?
Meh, Thor is not a brand I'd recommend, but that's just my opinion - others will disagree. But, in terms of older RVs, one tall pole to consider is technology changes. Things like TVs and similar components in the "house" tend to be built-in to woodwork, and they eventually require replacement. It's likely that older equipment will no longer be available for purchase, necessitating buying something different, which may not fit in the space the old item used. That's when things get interesting. 'Nuff said.
If anyone has any advice as to why a 5th or class A or Super C, I would be interested in your advice. I can think of some major reasons for staying away from a diesel or larger rv like the cost of maintenance, tires, repairs, etc. But buying a truck and a trailer has its disadvantages as well.
Regarding advice, it seems to me that you'll just have to decide which option best fits your priorities.
For example, we chose our Class A size simply because we like the space it offers inside - a 23' Class C we rented years ago to get a sense of whether RVing appealed to us was so short the bed was adjacent to the kitchen - way to small for us. So we're in our 43' Class A now, which we like.
Cost of maintenance, etc - yeah, it comes with the territory. Test-drive both - a Class A gasser, and a diesel. The differences in terms of ride quality, power, stability, steering feel, yada, yada become immediately obvious - it's night and day. But there's the maintenance tail you refer to - I paid close to $10K recently to replace all 8 of our RV tires - OUCH! But as the saying goes, "If you want to play, you have to pay", right?
