If you are hitting crystal springs as a day trip from Eureka Springs the Wal Mart museum in downtown Bentonville is pretty cool and there is an old fashions soda shop at the end.
Is you are on a bike or sporty car you can take the pig trail down towards Hot Spring on your way south. There is still some fall colors in central Arkansas, but might be gone up north already. This ride can get some people car sick if that bothers anyone with you.
At petite jean, bring walking shoes and take the waterfall trail down and back out. I am fat slow and out of shape and I can make it easily. If it is raining or has rained be careful it can be slick. Not many good eating options around the park in Morrilton.
Hot springs, you can actually go into one of the old steam caves the Indians used at one of the bath houses downtown. I think it is The Quapa bath house, but you need to double check and make reservations. Really good breakfast at The Pancake House downtown. 501 Prime is a newer higher end steak house and priced accordingly, but a decent bourbon selection for the area. There is a brewery now in one of the old bath house downtown as well, and a new distillery. I have not been to either yet, but I have heard they are good. Steinhaus Keller is a good German food place downtown. Not sure when you are heading up, but Garvin gardens does a Christmas light drive through, and the lines can be long, so get tickets early or go just before it is getting dark. There is also a scenic drive between hwy 9 and hwy 7 near Jessieville that has some great views. It is about 15 miles or so of good dirt road and has a few spots to stop and have a picnic along the way.
If you are a bourbon guy, you can swing into Little Rock and go to Rock Town distillery. They are putting out decent booze and Phill the owner is an Aggie.
I am guessing you may be heading back on I-30, and the historic town of Washington is not a bad stop. It is a state park and a little community that has been pretty well preserved. There is a small diner in an old house that usually has good lunch specials, but their menu has been limited due to the 'Rona. Take the Hope exit and head north past the airport.
The only other thing I will add it look at the google or waze drive times. Some of the roads here are curvy and slow going. Not at all like Texas where 60 miles is under an hour. State trooper here will usually not give 10 over so I keep it at 5-7 over except through the smaller towns.