Crossing the Rockies in a 172

Hi, I am in the planning stage for a trip from Kenosha (SE Wisconsin)
to San Diego to visit my brother this summer. This will be my firsrt
time in the mountains, and I was looking for some help picking the
route. So far I have picked up the WACs for the general area for
planning, and I was thinking of a northern route through SD with
perhaps a stop in Yellowstone on the way there and roughly following
route 66 on the way home.

What are some of the routes that would be acceptable in a 172SP or a
180 HP archer.

Thanks

Peter von Tresckow

P.S. I am planning on taking some dual in the mountains as well any
suggestions for that also??