First, Welcome! You sound like it'll be fun having you around.
We're a senior couple in a 31 without slides.
Most larger C's are on Ford chassis and average best MPG is around 8. Chevy does a little better but uncommon in 30+ feet.
Storage in our suburban area is about $100/month.
An on board generator will likely be an Onan 4KY series. Any Genny will be trouble if you don't exercise it by running under load monthly. Onan has the best parts and service availability.
More and more people are getting into RVing, but it's still a guess whether bunkhouse will continue to be harder to re-sell.
We're in Class C for just what you found. If you don't have need or want a serious truck, a C is the least expensive way into the RV arena.