Just to reiterate what has been said; there are a lot of smart and experienced people here. Flying is much more than take-off, landing and flying around the patch. Not only is there all the "book learning" but all the experiences you should handle first in a lesser complex aircraft. Noticed you have children. You wouldn't have them learn a two wheel bicycle without training wheels before riding anything, would you? Give yourself the same opportunities to learn in spite of the emotional desires. By the time you earn your PPL and Instrument Rating, hopefully you will have survived a sufficent number of in-flight emergencies due to weather, mechanical and personal factors. Once you have those experiences behind you, step up to a complex aircraft and go through those experiences again. They will still be a handful the second time around, but you have a better chance of survivng them.
As far as flying across the Sierras; I don't not know specifically. I have flown (both ways) across the lower Rockies in New Mexico & Arizona. There I saw vertical speeds in excess of 2000 fpm (3000 ft above the ridges). Also experienced winds so strong I could not climb above the ridge on departure from Calsbad, NM. Waited for a day and half under clear blue skies for the winds to calm. Found out later that a 727 at 28000 experienced severe turbulence that day and made an emergency landing. A flight attendant was severly injured.
I bought my first plane, 1958 C-172 in 1975.