Thinking about a Class A

When you look at any of them, check the fresh water capacity. My 5th wheel toyhauler had 98 gallons of fresh water which was good for two people for about a week. I just made the move from that trailer to a class A and we love it. The fresh water capacity is nothing to write home about, it's 40 gallons or so. A 4 day adventure and the tank is dry, and that's being very conservative. Look for something with at least 100 gallon capacity. Most of the class C's are gonna have a very small fresh water tank, like 30 or 40 gallons. The ford F53 chassis is much better than the chevy P30 chassis. It's built more like a truck. The V10 is a good powerplant, the 460 ford and the chevy 454's are all pretty lazy in the power department. Check the date on the tires, as 6 new tires can reach upwards of $2500. Good luck!

Although I personally prefer a class A, you are probably better off getting a class C with the overhead bed. You may also want to take a look at some of the newer entry level class As that offer a retractable bed above the cockpit area. Good luck!

As retired full timers in a diesel pusher, our situation certainly is not related to yours. However we camped while raising 4 kids so I have ideas on the subject.
1. New or used? I recommend used so someone else takes the first big depreciation hit.
2. Sleeping accommodations. 3 is complicated. Ever consider leaving one at a rest area? Just kidding of course. Bunk bed floor plans are great but then one is odd man out unless 2 are compatable enough to sleep in the same bunk. Perhaps even by modifying the platform to make it wider. Of course one could prefer the larger area of the sofa or dinette.

The issue of storage for long periods is common for motorhomes. My personal belief is that the generator should be run at least monthly and it should be run under minimum of 1/2 load for 30-45 minutes. I would not run the chassis engine unless I was able to take it out for a drive long enough to get it up to operating temp for a few miles.

I would add a fuel stableizer and fill the tank before storage.

With your situation, here is a motorhome brand and model I would personally consider:

2010 Winnie Vista

Monaco Monarch 2010
This year model is not special just an example. They are both available in bunk as well as conventional floor plans. Shopping used makes it more important to be willing to travel widely to make a purchase.

Good luck with your decision and have safe travels.