I recently picked up an '84 Class A (Allegro M-31). I'm not sure how far back you're looking, but the P30 Chevy chassis had carbs on the 454s up through '89 (someone else mentioned this). It's a reliable setup, even with the carb. The carb does take some occasional tinkering but in my case I stumbled across the rig super-cheap so I wasn't picky about carb vs. TBI vs. MPFI. It's easy to work on and simple in design.
Mine has a rear bedroom with twin beds, which is sort of unusual. Most have queens in the back. The twins are an advantage for kids that are too old to comfortably sleep in the same bed, but like to be in the same room. My couch becomes a sort-of-double bed that sleeps 2 adults cozily. There's also a bunk in the cab that *could* sleep 2 pre-teen kids but I'd recommend putting just one up there. Long story longer, the rig is great for my wife-to-be and 3 kids (16, 13 and 10). I, too, share custody of my kids (the 13 and 10 year-olds) and have found that RVing has been a great way to make the best use of our time together.
What I like most about the Class A is that the cab becomes more of an extension of living space than the Class C. I have a front living room and can turn the cab captain's chairs around to become part of that space. However, had a Class C fallen into my lap inexpensively, I'd probably be singing the praises of it instead.
It's not an inexpensive endeavor, and the older the rig the more potential there is for potential problems. Expensive ones. Any sort of leak or leaks can cause a lot of damage. The fridge is next the list- they don't age well. Beyond those two things, however, the rest of an RV isn't terribly complicated to repair or modify. I look at mine as an open palette for me to make my own.
Good luck with your decision!
1984 Allegro M-31 (Dead Metal)