If you do a search on "seat belts" and "child seats", you'll find that many, if not all, older RVs lack proper restraints in the house area to provide proper safety for little kids. Even those that you find with seat belts, the belts are just screwed into a piece of plywood under the cushion.
I completely understand your wish for a class C, I love mine.
But, you don't have any mechanical skills, you have 2 kids under 5 years, you don't have a lot of money to spend on a newer RV, etc. In addition, your last question about which class C is the best option shows your lack of knowledge in the area. No one can answer that question without seeing and examining each RV in question. You have to look at the condition of the engines, appliances, etc. as well as potential leaks and body damage. I think getting an older class c at this point isn't worth the convenience of the class c.
Since you want to get out and go now, and you plan on selling and upgrading later on, I think the pop-up is a much better solution.
A pop-up does require a bit more work to get on the go, but the initial purchase cost will be lower and there will be fewer things to go wrong (the engine will be your trusty pilot's) and you don't have to worry about lack of child safety restraints. You can start buying bedding, kitchen wear, etc. for the pop-up and use it when you upgrade. In addition, you can figure out what layout would work better for you. For instance, do you want to have to take down the dinette each night and put it up each morning? If not, are you and your wife going to sleep in the cabover bunk? What about the baby? Using a pop-up or other small trailer will allow you to decide what will work best while enjoying the outdoors and without putting a lot of money into paying others to fix the problems in an older class c.
