I have been working on a plan, to drive across the United States, including several stops in Canada, that will take me 45 days. But that is only if I spend 12-24 hours at each spot. (I was thinking I can get there for sunset, stay the night, and get sunrise, and I will be there for the best lighting scenarios)
Driving, with 24mpg, it would cost a total of $10k (including hotel, gas, and food). This is just to help you get a rough estimate of the cost. My plan was\is, driving from Southern California, up to Seattle, up to close to mid-Canada, then down to northern USA, and then drive over to New York, then go down to Florida, and drive back in Southern USA, lol... So it literally is\was around the country.
Anyway, good luck with this! I plan to be carrying out my plan (I might extend it to 24-48 hours per stop) in a few years (lol, I am only 15, so, I will probably do it in 2011 when I am 18, or 19.). Again, good luck 