great site. years ago i took a family road trip to yellowstone during the summer months and i believe it took about 17 days. this spring break i am looking for another trip out west, but perhaps save yellowstone for another trip and opt for a closer destination. we're amateur filmakers hoping to see the some of the "classic" tourist spots, those best for interesting people who would jump at the chance to be interviewed. wall drug, corn palace, deadwood and things of that nature...and balance it out with the badlands, custer, and the more natural beauty of the country. what would be a good final destination for the trip? ending on anything but yellowstone may be anticlimatic, but for a short trip (a week tops) on very little money (we're all students) is it possible to keep yellowstone in the picture?
Sounds like you've already got one
Considering your money/timeframe, and what you want to do, I think you've already got a pretty good itinerary mapped out.
In terms of a "final destination," it already sounds like you've got a good plan towards making it the Black Hills. Considering you'll spend a full day driving there and back, that would give you five days to explore the area. Which if you hit Badlands, Custer, Rushmore, Crazy Horse, and Deadwood would be a nice leasurely pace. You could also check out Devils Tower in Wyoming and/or Teddy Roosevelt NP in North Dakota before heading back.
Now that said, if you really want to see Yellowstone, you could do it in a week, but you'd probably have to skip some of the things you mention like the Badlands or Custer. Its a pretty solid two day drive from Minneapolis to Yellowstone, so giving yourself a week, you'd basically have 3 days to enjoy yourselves. Since places like the Corn Palace, Wall Drug, and Deadwood are all on the way, you could probably stop at them briefly, but you'd have to plan it a little more carefully so you don't get to those places in the middle of the night.