I have been wondering how you were doing with the "air leak" project was going. Thanks for the update. Sorry that you are having so much trouble resolving the problems.
Concerning wind issues, when parked, I think you are safe in anything but a tornado and even there a few of us have had discussions about what to do. The prevailing thought is to abandon the bus in a tornado if there is a safe alternative (big ditch or strong structural building designated as a shelter. We were at a Converted Coach rally in MN a couple of years ago and a tornado hit close by. The designated shelter was a cinder block toilet building (do you die in your bus or the crapper
). Kind of gets your attention.
As far as driving, I would not drive in a 75 MPH wind. Especially if it is gusting. Too easy to loose steering control. A couple of years ago, we were heading down I-25 close to where you are. There was a big overhead electronic sign that said if your were oversize and caught on the road, you would be stopped and fined $500. That area is terrible about gusting side winds. I think it was in the 50-60 MPH range and it was white knuckles when I passed a truck - and my Eagle is pretty darn stable. I was glad that they made us get off the road. As usual, we were on a tight schedule and had to drive a long day the next day, but at least we were safe.