Sheep - if you're gonna take Megabus, reserve NOW (well, as soon as possible after we figure out the date). There's some tickets left at the ~20$ one way price, only if you leave on Friday and return on Monday. On any other day around that, it's ~$40 one way already. ^^

megabus.com - low cost, daily, express bus service in the US

The ticket prices vary depending on demand and they fill rather quickly.