Long post but I've pretty much have run out of stuff I can bolt to the chassis. In order based on what I thought returned the best bang for the buck-
Cheap Handling Fix (aka CHF) - Very long posting on IRV2.com. Basically changing the dynamics of the Ford installed sway bars to increase body sway resistance.
IRV2 CHF Thread. My cost $0
Tire pressure - Either use the builder's placard listed pressures or get the coach weight checked with you normal loading (including people) and set the tire pressure per the tire OEM charts. I noticed at around 10 or 15 PSI high for cold pressure I could not keep the coach in lane. My cost $10 at a Cat Scale.
Koni Shocks - Was a bit hard on the coach budget (about $150 each) but ended up being a nice ride improvement over original. My cost around $450.
Panhard bar, track bar, or track rod - CHF reduced but did not eliminate tail push caused by cross winds or passing vehicles but once I added a track bar I've been surprised by 18 wheelers that suddenly appeared at my left elbow. My cost $600.
For wind handling I would not go much further. I have other add ons (air bags, steering stabilizer) but for the most part the what I listed had the most dramatic effect to counter wind.
Was out when the a edge of Hurricane Sandy passed by. Constant 30 to 40 MPH cross winds but the coach movement was very manageable
Almost forgot, the coach is build on a 2006 18K lbs GVWR F53. Normal load weight is around 17,250 and I tow a 2005 Honda CRV which weighs around 3500 lbs. Your results will naturally very.