I think that the big thing for a cl c is that you can let the kids go potty while driving. I have both a 28 ft Cl B+ and a 24 TT. Personally I prefer the TT as I enjoy my truck (F350 PSD), but wife wanted and we got the RV. She like the ability to potty without stopping, for the driver its a wash. The TT once in place can be all done in 10-15 Mins, the RV depending on spot is about the same even with 'levelers'. The RV sits and takes up space as does the TT by there is no need to run a gen or the RV's engine monthly. The tow vehicle, depending on what you want is or can be a daily driver. So really it all depends on your $$ situation, can you afford the TT and Veh, or is the RV better suited. Nice used tow and TT are available usually for a lot less than a RV unless getting one 10+ years old. Depending on the kids age a TT may be better since the rv generally does not have suitable sitting positions in them for passengers. The tow vehicle can be set up with the kids chairs if required very easily.
So it comes down to your actual wants and needs as you see them. A short RV will be more than likely uncomfortable for a growing family (based on experience with a slide in camper) and a trailer will take some time to adjust to for you and your wife if she plans to drive. Mine does not in either vehicle so I do all the driving and set up, she is in charge of the interior of the truck (sodas, snacks etc) and the coach of the rv. We have no kids to worry about :) Also with the RV you will in at least 90% of cases want a towed veh for day trips runs to store etc although many here claim convenience with short rv's, Most I see even short ones have a towed behind them, the TT vehicle takes care of that issue.
