Over the years, I've made several road trips in the 2,000 - 3,000 mile range, one in the HCH. They hybrid was fine -- no different than a standard car. But I can tell you this; If you drive 4,500 miles in one week, it won't be any fun, because all you'll do is drive.
Through the western U.S. you can average 70
mph on the road, including fuel and food stops. But to get 4,500 miles, you'll have to average 600+ miles per day, which means nine hours of driving per day. Maybe more if you go through the rocky mountains.
So side trips and sightseeing will be difficult, if not impossible. And that really negates the value of a road trip, doesn't it?
Are you sure you want to do it?