My 2 cents:
I just got back from a SC to CA, north to Glacier N.P, back to SC loop...about 9k miles...in 17 days.
In a rental car. It was fun but BRUTAL. I do not yet own one of these great machines, but there is no way I would make a cross country drive in a vehicle like that unless I planned to span it over 2+ weeks just one way and camp, hike, and site-see along the way.
Otherwise it is just WAY more trouble than it's worth. Remember...it's not just fuel costs.
3k miles on the tires. 3k miles towards needing an oil change. Wear on the brakes coming out of the Rockies, etc.
Now, as I said, I don't own one of these yet, so some of these things might be a bigger or smaller issue than in a regular vehicle. But, I would either make it an amazing "trip of a lifetime" type event or buy local....or ship it.