Be aware even in that time frame, there will be a lot of driving It took us 4 days of straight all day driving to get to WA from ND, and we knew the roads etc. If they are staying in motels, plan on spending at least 100.00 per day or more . Food is high and when we traveled with kids years ago, we tried to stop at smaller towns with parks and let the kids play/run around and have picnics. Make sure they have good road maps, and stop and the welcome centers on the interstate for information. Try to stay on the main highways and stop at the rest stops. From St Paul to WA use the northern highways, like 94, avoid Williston due to the heavy oil traffic. They probably won't have much time to see anything off the beaten track. Make sure they have snacks, bottled water for the kids, and keep the meds available , like upset tummies, etc. Keep the menus simple and similar to what they are use to eating. Try to stop for lunch, if not at a park, around 11:30, before the rush traffic, and plan to stop for motels around 5pm and eat before the supper crowd. Hope this gives you some helpful hints. Try to stay with the chain restaurants, and avoid the local ones, We liked Denney's, Perkins etc
Many motels have something quite close to walk to.

Thank you Marie. What are some more restaurant chains?? Like we don't have Perkins down here in AL and they don't have Perkins in Nebraska either. I know about them from when we lived in CT. She really liked the idea of getting food to go and eating in a park.

How far off 94 is Mt. Rushmore?

Please keep the suggestions coming...

easiest best thing to do is use google maps and follow the route they are taking in the areas they think they might stay just do a google map search for that area for restaurants and hotels. That is what I do anytime we are traveling. It is so great you can even go into street view and see what the place looks like up close and helps to locate it by seeing the street and what is around it.
And each time you do a search for say a restaurant and it pops up a suggestion there are comments from real people that have eaten there and how they liked it or not. It is really the best way to do this kind of thing.
Plus doing that and looking up lodging you can often times find online specials through the links that come up.

If they are not familiar with how to use google maps I suggest they get started learning now it is such a wonderful tool for that kind of thing.
There are also great apps for smartphones and tablets that help in those types of situations. It is one of the good things from our technology.

We had taken a trip recently and were hungry and wanted a good place to eat. I grabbed my phone and put in a search on google for restaurants in that town in the area we were in. Turns out the highest rated restaurant was just about a block down the street from where we were getting gas. It was a wonderful restaurant and you knew it was because it had lots of customers and several were police officers. I would definitely go back there if we are in the area again.

I find new places to try out here in my area by doing the searches from my home address and just keep moving in different locations to see what pops up.

Good they have almost a month to travel. When they are in Des Moines, there is a wonderful zoo and a science center the kids will enjoy. Since they will be there a few days, they might want to make the 40 min. drive to Ames and eat either lunch or dinner at Hickory Park. It is famous for it's BBQ and is very kid friendly with a big ice cream menu. Harrison Ford had lunch there when he and my cousin were flying from coast to coast and landed in Ames for fuel.

Sounds like a good chance to go exploring and learn new areas. I'd try all the town/city restaurants just for something different. We traveled from California to Tennessee when we moved here in 1977(?). Fantastic to see all the scenary and meet folks from all over. Yep, I'd grab my phone and use it as GPS and/or restaurant finder. Most recently, I drove to what I thought was the right auto parts store, but it was 100% wrong. I would've driven back across town had I not realized my phone could tell me. I was a block away. Amazing what technology can do to help you nowadays. I would still map out a course using actual maps, but a GPS can get you around when there's a hiccup in what you've planned.

Raven- I will tell them about the google maps and how to look up restaurants on her phone.

Linda- They are only planning on stay in Des Moines a day. Just to visit his grandfather. Same goes for St. Paul.

I am loving these suggestions please tell me more.

Thanks Raven for the idea of googleing--completely forgot about that. In fact I belong to AAA and you can do a triptick thru there website. I just did for the area in Ore/No Calif.
Mount Rushmore is a couple days drive from me in Minot, Not sure how your friends want to leave from St Paul. The only reason I suggested the northern interstate is less traffic, but St Paul might be too far south for that.