this may help you
http://www.coloradopilots.org/page_mtnfly_passes.htm

its the passes in the colorado area with the elevations and such.
I have always been told not to attempt to cross the rockies when the wind at
the top of the mountains are 30 kts or more.

RD wrote:

I'm planning on doing a trip from central Canada down to Las Vegas in a
C172R. Does anyone have some experience on where a good point to transition
the US rockies is? Somewhere around SLC is my guess. I have no mountain
experience which causes me the greatest concern. Any help appreciated.

--
Thank You,
Ryan