My family and I have a cabin east of Clinton and drive that road about 5 times a year. It is very curvy and hilly between Clinton and Harrison, but it is scenic, the roads are smooth, and there are many passing lanes up the hills. From Little Rock to Clinton and from Harrison to Branson is all 4 lanes.
I recommend stopping for breakfast or lunch at Ferguson's which is just north of Marshall. We have had no problems with a big motorhome pulling a toad through the north side of their lot. For a more adventuresome side trip drive down to Gilbert which is just east of Ferguson's. It has an RV campground and access to the Buffalo river. There is no off street parking except for the campground, but it is a sleepy little town off season and parking on the road is no problem.
There is a WallMart in Conway, Clinton, and Harrison right on 65.