There's so much in the Mt.Rushmore/Badlands area that you could easily spend a lot more than 3 days/2 nights there. But, for a quick overview, I guess it's enough.

Wall Drug is nothing but a tourist trap.

I would definitely agree with ronkala about Wall Drug. There are much better ways to spend your limited time in the area. Custer State Park, for example.

From Red Lodge you will be coming in on the Beartooth Highway (212) BEAUTIFUL drive! Best entrance into the park, IMHO.

Since you will be flying out of Rapid City, it looks pretty good!

If you spent the night in Gillette (329 miles and about 6 hour of driving time), then the next morning you could take the detour up to Devils Tower National Monument before going to Rapid City. You might also want to make a little detour to Deadwood, SC. On the way to Gillette you might want to spend some time in Cody, WY.

Utahtea

Be sure to stop at Devil's Tower on your way to Rapid City/Mt Rushmore. It's the USA's first national monument in the NPS and is a 1200+ high volcanic tower in the middle of a flat grassland plain. Most people recognize it from it's prominent part in "Close Encounters of the Third Kind". Also near Rapid City is Deadwood and Sturgis as well as Custer National Forest and Windcave National Park.

For the Rapid City part of your trip, I agree that you should definately skip the Wall drug store, it was very touristy and crowded. I highly recommend Custer State Park in addition to the Badlands and Mt Rushmore. Custer was beautiful, and there was ALOT to do there and the wildlife was quite abundant. If you can squeeze it in, try to drive up to Devils Tower in Wy. It's only about an hour away and was alot of fun.

Also Jewel Cave & Wind Cave (national parks/monuments - forget which) in the Black Hills area. Could take a tour in one of those, if you like caves.

Agree Custer State Park is very nice. We rented a cabin there & woke up in the morning to a bison grazing right under our window! Dinner in the park at the 'summer white house' - forget its real name - is also quite good.

Custer State Park is delightful. Be sure to take their 'buffalo' tour which drives you into these herds and as close as you would ever want to be. We saw antelope and other wildlife there. Getting confused we saw and did so many things on the trip that included CSP, but I'm NOT confused about the buffalo! Truly entertaining afternoon.

Don't forget to check out the Crazy Horse monument!

With your limited time, here's another vote for skipping Wall Drug! You could easily spend a week in the area, but since you only have a couple days, I would recommend you take the scenic drive "loop" out of Rapid City - Go South to see Custer State Park, Jewel Cave, Mammoth Dig Site. Go North to go to Deadwood. (Mt. Rushmore in the middle). We were there just this past Fall - Deadwood is no longer the rustic town it used to be (casinos took over), it has some fun activities, but with your limited time I would stick to the other sites. Badlands would also be a better use of time.

We did pretty much this trip last September. Flew into Billings on a Saturday and out on Saturday 2 weeks later. We spent the first night in Red Lodge, 3 nights at the Lake Hotel in YNP, 3 nights at Signal Mtn. Lodge, a night in Cody, a night in Buffalo, WY, 4 nights in Custer, and our last night back in Billings before our flight home.

It was a lot of driving but well worth it. I'd skip the night in Jackson and spend the extra night in GTNP or YNP. Jackson was ok, but the fabulous scenery and wildlife in the parks is so much better. I definitely agree with the posters who urge you to go to Devil's Tower on your way to the Mt. Rushmore area--it was one of the highlights and the drive to and from it is quite pretty.

Custer State Park is definitely worth your time--it has some great scenic drives. We had planned on doing a buffalo safari there, but after getting as up close and personal with the buffalo in YNP as we cared to, didn't bother with the safari in Custer. We stayed in a cabin in Custer and my only complaint was that it was right on the main road throught the park and we started hearing traffice very early in the morning--before 6.

I think your arrangement of nights in YNP is great if you can get the reservations. The park is so big that it's worth it to move locations, which we didn't do.

This was our first trip to the area also and we wanted to see as much as possible --and there is so much worth seeing.

PS, I posted trip reports on this trip with more details if you want to search on my name.

Of course Wall Drug is a tourist trap -- that is the whole basis of the interesting history of the place. You don't need to spend much time, but its at least worth a pit stop for a cold drink or ice cream cone.

I would skip the 2 nights in Mammoth. You can see the hot springs in about two hours. I would drive through Mammoth, see the springs, and then drive to Canyon Village(or Old Faithful) for two nights. If you go to Old Faithful before Canyon, you can easily stay in Canyon for two nights after your one night in Lake Yellowstone and after your GTNP visit. (Canyon & Old Faithful were my two favorite areas.)

I also would question your reason to stay in Mammoth Hot Springs for 2 nights.

We spent 2 nights in Rapid City at the end of a long trip such as yours and found that it was long enough for us to see everything we wanted to. Also stopped at Devil's Tower on the way and was very glad we did. We also stopped at a Prairie Dog town that was right next to that if I remember right and really enjoyed seeing them. We went to Badlands and stopped at Wall Drug, neither of which I would do again, but was very glad I saw both because I would always wonder what I had missed. Isn't Wall Drug on the way to Badlands? I think it is worth a stop--we just walked through and got an ice cream--just to satisfy your curiosity, especially after you have been looking at many, many billboards advertising it along the way. We went to Custer Park and saw the buffalo (but agree with RuthMc that you see many in Yellowstone) and did the Needles Road to get there and really enjoyed that. We drove to Wind Cave, but the tours were done for the day--so call ahead if you are going to do that. We saw Mt. Rushmore in the day and went back at night to see it lit up.

We thought the ride across Wyoming would be pretty flat and boring and were very pleasantly surprised at how scenic it was.