We routinely travel from Michigan to somewhere in the south and site see along the way. We do not take direct routes. Not quite 5000, but it doesn't bother me to drive. I drove 17 hours straight more than once when the need arose. DH would have a harder time driving a lot of miles in a short time than I would.
To the OP and wife -- our class A felt like it was doing a lot of rockin and rollin also. We did 2 things that have helped -- if you have an F53 chassis, check out the cheap F53 fix. It will stiffen the ride a little, but help top the rockin and rollin. We did it and DH said he wished he had known about it 3 years ago. We also put a steering stabalizer on so that if we did go off the road or had a tire blow the steering would automatically return to center to help keep control. I have not ridden in the coach since this was done, but I can tell from following that it make a huge difference. I would probably rather drive than ride.