Before I say anything, I will tell you that we camped with our kids in a pop-up, and then moved to a travel trailer when they were in college. We've never owned a class c or any type of motorhome.
The following points popped into my mind after reading your post:
1. If traveling with two kids....soon to be bigger teenagers, does the class C provide adequate sleeping quarters as well as space for their stuff?
2. Do you plan to travel with bikes?? Class c motorhomes can have a limited cargo capacity. From my point of view, they are great for a couple, but when I look at them at RV shows, I don't see traveling in them with two kids.
3. With two kids, I see the advantages of a TT or FW, with a truck that has room for bikes, sporting gear, etc. And, the truck can serve as a second vehicle for daily use. In our case, my wife had a very short drive to work and would take the truck.
4. I don't know the specifics, but make sure you know how towing a car on a dolly impacts your cargo capacity on a class c. At the same time, if you go t a TT/FW and truck, you have to look at the payload capacity of the truck.
5. Another advantage of the TT/FW option is that you can go ahead and buy a 3/4 or 1 ton truck and have plenty of towing capacity. You can look for a really good used trailer, use it for a year or two and determine whether it meets your needs. If you've determined that you would like something else, the financial impact will be minimal i.e. a good used trailer won't lose that much in value, and you don't have to worry about the truck.
But, bottom line is buy what you really want. By buying used, if the price is right, you can use it for a year or two and trade it in for something else if it doesn't meet your needs. I just always hate the sales tax bite!!
Good luck....hope your out there soon and enjoying a new rig!!