We are doing a road trip too. It will be more biking/camping/lakes/beers, not so much for historic sites.
But as rough draft, I want to spend a couple days at Lake Chelan, then south from there. Probably through Yakima then west to Portland to see a friend there. Then from there, we will continue south, no really set plans. As long as we are in LA at the end of July for X-Games (**** I CAN"T WAIT...) scuse my potty mouth.
Then, on the way home, I think we are going to take our time through Hwy 40 Arizona and roast our butts off. Then up through Bryce Canyon possibly? Work our way over to Colorado. Colorado, there is so many mountains and areas to choose from, we are going to just wing it. From there we will make our way back to BC through Utah and Idaho. Come back in through the Creston/Porthill border crossing so I get my Kootenays fix. Kootenays mid summer, you can't beat it.