Questions on driving thru Rocky Mountains on I-90?

Question

May 1st I will be driving from Wisconsin to Oregon using I-90 through SD, WY, and Montana.
I am wondering just how scary this is? I will have a fairly new car (manual) with no trailer. But I am terrified of heights (even high overpasses on a normal highway). Is the highway through the Rockies very steep? And are there parts where you're just looking down the side of a mountain or cliff on the side of your car?
How long does it take to drive through the Rockies? How many individual 'mountains' can I expect to go over and how long does it take to cross each one?
I cant find any good pictures online of what its really like to drive through the Rockies via Montana/Idaho, then down to Portland.

oh, and will there be snow or icy roads around May 1? I am an inexperienced traveller, and have never been through mountains or anything other than the very flat lands of the midwest!

Answer 1

I have only driven on I90 as far as Missoula. Not bad.
I also don't like steep drop offs or high bridges and I made it.
There can be snow in May at high altitude but the highways are kept clear.
The change in altitude is gradual so not that noticeable.
Relax and enjoy the trip.

Answer 2

Driving through there shouldnt be that bad at that time of year. I also drove from wisconsin to northern montana. i did it in january and it was ok then. i dont know what to tell you about your fear of hights. i will tell you that it is alot better than driving through colorado. montana isnt nearly as steep as colorado. S.D. is flat and i dont know about W.Y. Just keep your speed down when you are traveling down hill and down shift to keep speed and power going up. Mabye you could check wikipedia for descripitons of those states and the mnts in them.