We are a family of 5 and we've stayed in the cabins. I loved the campgrounds as did the whole family. My question is though- do you want to be at the campground and do things there? If not, then one of the other resorts may be more worth it so to speak. The internal buses are not like the rest of the transportation buses- there is *usually* less than a 5 minute wait and the buses aren't full at all. However, when we stayed, we did rent a golf cart, which you should consider.
However, the thing is with 4 adults and two kids- I don't think a standard golf cart would work. If you did decide to do a golf cart you probably want the extra large kind and you probably would want to do it from an offsite company.
Is a golf cart totally needed? No, especially if the vast majority of your time will be in the parks all day from morning til night. It is no longer of a walk from most of the bus stops to your cabin door than it would be from any other bus at other resorts (in fact probably closer).
Transportation isn't really very hard from the Cabins. You can take the boat to MK or the boat to Contemporary and then monorail to EPCOT. Buses to AK/DHS and Downtown Disney. It was nice having the boat option.
I loved the campgrounds and would do it again in a heart beat, but you need to just think out the logistics and make sure it is a good fit. If you are looking for space, I would *think* that the cabins would suffice but keep in mind you'll need to put the murphy bed up if you want to easily use the bigger couch. Your parents may want to take the front room and you and your kids could be back bedroom. The porch is roomy and as long as you can all deal with one bathroom you probably won't feel too cramped.
You may really enjoy the different experience. It is fun to come back from the parks at night to a homey cabins with your own "space". I think it's the *best fit* if you are looking forward to the campground itself.
Some folks questioned whether you should "do the dining plan" if you are staying in a cabin as you have a full kitchen. We had no problems, I used a lot of our snacks to keep the fridge stocked. We bought a few minimal groceries and we were able to use 2 TS for the Hoop Dee Doo revue and we always had plenty of food. Hint: you can do the pizza from the Trails to Go and that only uses 2 quick services and you get a full size pizza and two drinks and two desserts.
I haven't stayed at POP. I've researched it. Staying in Ft Wilderness to me have just lots to do everywhere but it's not "fancy" per se. It was as if they made Frontierland come to life and you got to stay in it.
especially 4 adults and then 2 kids!! It's going to take forever for everyone to get ready to go! Even with some people showering the night before, I think you are still going to be shocked how long it takes for you guys to get out the door in the morning with just one bathroom. I would go with the two rooms at POP! It's kind of a shame that the AoA suites get the same dining plan because that would probably be a great fit but since you have to pay rack rate for the room to get 
