It sounds like a fun plan, but it would be more fun if you could take more than 7 days to do the trip. Make a real vacation out of it! You need to identify something that interests each member of your family, then plan a stay over where that person's interest is fulfilled. For example, if your son is into trains, plan on stopping at a Rail Road museum that also has a real train you can ride. Or if your daughter is into doll houses, maybe a museum of miniatures. If another child is really wanting to go to a Theme Park with rides and water slides, plan a day at one. You get the idea. Make the trip meaningful for everyone. 50 years from now, they will be telling their grandkids about the time they traveled across the Unites States in a covered wagon! (well, 50 years from now, who knows what kind of transportation we'll be using?)
Then draw a straight line from point A to Point B on a map, and see where you have to deviate to reach all of these destination points. That's probably the best trip planning you can do. Everything else will fall in line... campgrounds and such.
But I do certainly hope you can put more time in the schedule to make it really a powerful trip for everyone!
FYI, we traveled with a pet chicken, a rabbit, cat, dog, fish, an iguana, turtle, mice, hamster, guinea pigs, and 3 birds for years! Never had the experience of traveling with a pig though.
