Jim mentioned two of the must do items before after market remedies are tried.
1. Determine the weight on each wheel, axle and total coach.
2. Get the tire pressure correct for the weight being carried.
3. Ensure all suspension parts are functioning correctly. No loose or worn parts or joints.
4. Two axle alignment, by a very repudable shop with the modern laser equipment.
The first after market product I would try is a suspension improvement. Go here
to see some suggestions. I do not know your chassis. Call the Super Steer folks at 888-898-3281 PT. Tell them about your concerns and chassis make. They can advise you of your choices. I always felt if I could stop the coach weight shift on the chassis, the steering would improve and the rock and roll would be reduced or eliminated. For my chassis, the air bag restrictors were a miracle. The improvement was immediate and dramatic. It was like having a completely different coach.
The second aftermarket product that might help is a steering stablizer. The one I like is also by Super Steer. Go here
to see the write up. I got the Howard System because Super Steer was not available for my chassis. If it had been available I would have purchased the Safe-T-Plus system, with the trim feature. The important thing to remember about this stablizer is it can be recentered by the driver, on the fly. Go here
to read about the trim unit. Being able to trim the steering unit on the fly is a very valuable feature. On days where the cross wind is pushing you all day long, you will bless the day you got the trim feature.
The third/fourth item(s) is/are an anti sway bar and a track bar for the rear axle. There are many different brands to choose from. I have the IPD Brand (now Roadmaster).
I recommend the Supersteer company because I like their products very much. Their products have a good reputation. The company has a full line of products for most chassis'. Many of these products are invented by the company.
Consider doing one thing at a time. Then you will know how much each item helped your coach. Also, you may not need all the products. This would get your coach the way you want it and not spend any more $s than necessary.
Good luck and post any questions you have.