Find a spot, or put a sticker, on the dash so that it lines up with the center line when you're about a foot or so inside the line and use that as a quick reference as to where you are on the road. Also, an old trucker rule is to check mirrors every 7 seconds, which also gives you good reference to where you are and also to check for vehicles around you. A quick glance is all that is needed. I know it's scary at first, but with a little practice it soon becomes easier and more relaxing. Of all the vehicles I own, I prefer driving the motorhome. Well, maybe second after my 1986 MR2. ;)
If it's too windy, and this is determined by individual drivers, get off the road till the wind dies down. I have spent more than a night in rest areas waiting for the wind to die down. Mornings and late afternoons are usually better times to avoid wind. It is quite a bit different driving a motorhome than any other vehicle, but hopefully you will learn to drive it with confidence. Hang in there! and GOOD LUCK!