Well, as a fellow family of 4 kids, I can tell you that we LOVED traveling in our MH. You know as well as I do that you will never coordinate the bladder schedules of kids...not to mention DW. So, far fewer stops along the road. Plus, it's awesome to be able to grab a snack or drink from the kitchen while traveling. We had a bunk model Itasca (Winnie) and it served us very well.
We recently sold it...and are eventually moving to a TT and full size van, as we are adopting so will need even more space. And there is the potential issue for you. You mention quite often having "tag alongs"...either other children or your Mom. Which is awesome. But that might make most MH's become pretty tight. Our bunk model class A was great...DW and I had the bedroom, the two youngest DD's had the bunks, and the two older DD's took the sofa and dinette in front. On the occassion we had to sleep an extra person, an inflatable mattress was placed on the floor near the sofa. There would not really have been any room for anyone else, short of throwing up a tent outside.
If you think you will routinely exceed 6 people, you may want to consider either one of the super C's with bunks AND the overcab bed option, or go the route of a bunkhouse TT. We are looking at models with a 4 bunk room in front, a nice sized master in back, plus we still have the sofa bed and dinette in the middle. We have a 12 passenger van to haul it all. So, once we are ready to dive back into RVing, that's the likely route we will take.
Good luck!