Unfortunately, the United States severely lacks in public transportation. Flying from State to State isn't such a bad idea if you can use the low budget airlines such as www.Spiritairlines.com, www.allegiantair.com, or Southwest Airlines. Sometimes the one way fairs far in advance (Like book now for November) are pretty good. As an example. Flying from LGA (LaGuardia, NYC) to Miami, Fl (FLL) is 94.00 USD one way on Spirit Airlines. This is the ultimate in low budget so expect no thrills. If you could plan big jumps like that and don't mind skipping large sections of the US it isn't so bad. Our train system. www.amtrak.com has to for some insane reason I have never figured out, route you through our Countries Capital. Washington, DC. So if I want to go from Greenville, SC to Florida. I have to travel via train 600 miles north switch trains, and then travel the 600 miles I just came, plus however many miles to my destination. Not to mention they aren't cheap. They are pretty good I have to admit if I am going from East to West Coast or vice versa. It just has a problem going North and South.
Greyhound busses can be a great value also. Beware though...you will definately meet some interesting people and see some of the smallest towns in the US. I travelled from San Diego, Ca to Greenville, SC. It took me three very long days, but it only cost me $94.00. If you are travelling with a buddy there are buy one get one free or half price also. Perhaps if you stay in local hostels and hook up with a travelling partner you could split the difference. The best deals there are at least two weeks in advance. The ticket will still be reasonable.
Just a quick question? Why avoid Las Vegas? I have travelled many cities and countries in the US and Europe. I would not pass up Las Vegas. It may seem like a lot of gambling, but there is nothing like it in Europe or the US. You don't have to gamble. Just people watching and seeing the free water show outside of the Bellagio is a site to behold. There actually is a hostel located just off the main strip that is great to lay your head. It can also be a jumping off point to see the Grand Canyon or any of the other local National Parks around there. Please give it a second thought. Kim