As was mentioned, get the coach weighed. If not on all four corners, at least get the front and rear axles weighed. MOST coaches will handle a lot better if the front axle is loaded close to the maximum weight allowed by your F-53 specs. If the front end is too light, the coach will tend to wander.
I also found with my coach that pulling a toad seems to stabilize the coach a little during high winds.
I also added four corner air bags and will inflate them up to around 80psi during high winds and reduce the air pressure when the winds subside.
With this combo I have driven in very high winds without any concern. Since we travel a lot in the Great Plains, high winds are the norm.
One thing that should also be done is to have someone else drive your coach, who is familiar with the way an F53 should handle, and then see if the problem is you or the chassis. Driving slow and fighting the coach is something you do only if you have a problem that cannot be corrected.