sway bar and steering stabilizer

There is no "here is the fix for all of them".

What aftermarket things are needed/desirable depends on a number of factors:

What chassis? Advice for a Workhorse P vs Workhorse W vs Ford will not be the same.

What length (actually Wheelbase/Overall Length)?

How is it loaded?

Getting moved around by the bow wave from a passing 18-wheeler will not be solved at all with sway bars, and a steering stabilizer will not help much either. A Trac bar on both the rear and front axles will keep the coach and the chassis tied together and help the most to eliminate sideways movement that you will notice from the wind.