Four of us are planning a trip from D.C. to the West Coast and back (may15-june8). We're heading out along the lower half of the states and returning through the upper half.

We cannot seem to create an optimal route through the western half of our trip while hitting all of our destinations. (everything in between Dallas and the Dakotas)

We are up for anything, but the main places we want to hit are as follows:

Cities-Dallas, San Diego, LA, San Fran, Vegas, Park City UT
Parks-Carlsbad Caverns, Grand Canyon, Yosemite, Redwood, Lake Tahoe, Mojave National Preserve

We would really appreciate any advice on any part of this portion of our trip. We are life long east coasters, so planning that part was no problem. It just seems we can't make it to all the places I mentioned above without some serious backtracking. (For example: grand canyons - before San Diego or after LV)

PLEASE HELP US!!!!!!!!
Thank you everyone

Alex