We are about 10 hrs from Toledo, oh. will make a descion in March if we fly, drive or don't go this year. Like most things depends on money.
I would love to drive, but being the only person doing the driving, not sure if I want to do 8 to 10hrs a day behind the wheel for 8 to 10 days
When we drive from Toledo I do an 8-5 "workday" with an hour break for lunch plus a 15 minute everytime we have to gas up-usually at lunch.
We also plan on being in hotels by 5-6 to take advantage of the pool to release any driving kinks and tire the kids out. ( I have neck back issues to work around, having the workday makes it still feel okay)
You can drive from Toledo to Rapid City or Custer, SD in 2 1/2 days without any sightseeing. We spend the other half day sightseeing as we need the break.
Toledo to Iowa,
Iowa to either Mitchell, SD (Corn Palace is free and a good chance to stretch the legs and get dinner) or to Chamberlain, SD if you can.
On the drive from Mitchell/Chamberlain --We either stop and see Minuteman Missile Site or go through the Badlands(have to choose), then go to Grasslands National Park see the movie and use the bathroom, Wall Drug to eat and gas up. Then drive to Custer (The half day from Mitchell to Custer, SD takes a whole day with all the stops)
Drop off luggage and see the evening program at Mt Rushmore.
We also usually make a 2 night stop at Mt Rushmore at the halfway mark because one of my kids has usually not been there before. We stay in Custer, SD when we do this as it is much closer.
If you are not doing this -stay in Rapid City, SD on the highway. See the night program either way.
Next day drive through the pigtails and do the day program at Mt Rushmore(go early to see the mountain goats in the parking lot) and drive around Custer State Park to see the bison.
Custer, SD to Bozeman, MT. We try to get an early start but do not always succeed. We also do not go back to Rapid City to head west- we know a short cut learned by sis when she lived there that makes the time the same as starting from Rapid City. (Going past Jewel Cave and cutting through Wyoming on nice roads- no traffic no amentities)
We have gone as far as Missoula, MT before we stopped for the night, but it was a really long day.
Bozeman, MT to Seattle, WA. We sometimes stop around Moses Lake, WA or the town before it if we got too late of a start to avoid driving into the sunset then driving through the pass in the dark. (I have an eye problem driving at night).
There is a faster way that goes through Chicago and Minneapolis and then through North Dakota. We did lose cell coverage in ND. I can drive Seattle rush hour, but Chicago toll booths starting and stopping scares me with the busy traffic and aggressive drivers (and this was at noon). There is a way to go farther west of the city before turning north and we will try that next time we go that route.
Our preferred route is through South Dakota as there are more less expensive options for where to stop for the night and more gas stations, places to eat. Also consistent cell phone coverage.