A rear trac bar/rear sway bar will help reduce or eliminate tail wag caused by towing. If the MH has a factory installed rear trac bar/rear sway bar there is a good chance it is under-sized for use in a MH.
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Quiet Hitch on the tow bar or draw bar takes the wiggle out of a loose receiver. A tow bar or draw bar that wiggles in the receiver can cause tail wag. It is a simple device that can vastly improve towing characteristics.
Review the owners manual for the tow bar. I have a Roadmaster Falcon 2. The Falcon 2's manual says that the tow bar's arm should be no more than +/- 3 inches from level when connected to the base plate of the toad. You may need to add an adapter in the MH's receiver to lower (or raise) the hitch height to bring the tow bar into the manufacturer's operating specifications for the tow bar.
Other potential performance improvements:
upgrade the shock absorbers
install/upgrade the front sway bar
replace the factor steering damper with a heavier duty version: like a Safe-T-Plus
Most of these suggestions happen because the cut-away chassis that many of the Class C MHs are built on were designed for delivery vans and not for the weight of an RV sitting on the chassis - and not all of the coach companies upgrade these parts in their Class C MHs. For many RVers replacing these parts with heavy duty versions is what is needed.