Unless you have a month or more to spend, it's best to become familar with the distances involved. I've many friends that come from the U.K.. and Europe that are constantly truly slack-jawed as the immensity of the nation. It's over 2,500 miles from New York to Los angeles, for example. Not only that, but after the first 500 miles or so, the driving scenery gets pretty repetitive. For example, if one were to drive from, say Chicago to Las Angeles in hopes of seeing Yellowstone and much of the wonderful country in my part of the U.S. (the inter-mountain west) one has to travel through Iowa, Nebraska, much of Wyoming and let me tell you, the jackrabbits have to carry their lunch. One can drive 150 miles between towns of any size. Not to mention that gasoline (your petrol) is now averaging $4.00 per gallon. I know, I know, ya'll have been paying more than that for a long time, but it's still a shock since the price rise has occurred over such a short time.
I'd investigate this site:
http://www.vacationsbyrail.com/usa/index.html? utm_source=google&utm_medium=ppc&utm_campaign= usa_rail_tours_general&utm_term=Rail+Tour+Unit ed+States&gclid=CKzwj-u-2ZMCFRTbQAod_E-VZQ (sorry for the long URL. Train travel can be enjoyable. But the best advice I can give you is to select a specific area of the country, such as New England, the west and its myriad National Parks or the West Coast and do a really in depth tour. (My personal favorite is New England, especially Boston on north to Vermont, New Hampshire and Maine to include New York City, of course. And that;s from a confirmed, dyed in the wool westerner.
Unless air travel is well planned and secured many weeks in advance, it get's real expensive real fast.
But, at any ra