Cycle touring is awesome. It's a great way to see the country. Instead of those giant interstates with your eyes glued to the car in front of you, you're out there on the country roads going nice and slow, enjoying (or cursing) every change in the weather and all the smells and sounds. It brings out the best in the locals -- I think most people are secretly (or openly) jealous of someone who leaves everything behind to go out to see the world. Even a recluse like myself winds up invited into grandma's for pie every so often. If you ever drive by a bike loaded down with gear, give them a holler of encouragement -- you have no idea how much it can lift their spirits.
It can also be very cheap: on my first trip I bought a $100 used Univega and made my own panniers. I used (don't laugh) this noxious blue woven polyurethane tarp material you find at Home Depot, and held it all together with nylon webbing, some aluminum poles, and (I kid you not) duct tape reinforced with some nominal stitching. (The stitching was an after-thought because it all started to fall apart after the first day.) I could camp just about anywhere: just haul the old beast off into a forest, field, behind a church, under a bridge, etc. and no one's the wiser. It's a lot easier in the back-country, obviously -- cities and the relatively heavily populated East Coast are a bit trickier. But a few rules of thumb help: leave camp at first light and no one will ever see you. And for god's sake, never build a fire -- try not to leave any trace, in fact. It'll help protect the reputation of cyclists everywhere.
There is one thing you need to know before quiting your job and riding out the door into the great unknown: learn how to fix the darn bike. I got so many flat tires I can't begin to count them all. On any long trip you really want to know how to adjust your brakes, gears, and chain. The chain lengthens over time, especially in rough conditions. It helps to lube the chain properly -- don't use motor oil or WD40!!! Use one of those fancy waxy ones that cost a lot; use a small amount frequently -- like once a day. It's good to know what to do about broken spokes, too. You don't really have to be able to replace them (the ones on the gear-side of the rear wheel are extremely difficult to replace in the field -- but not impossible), but at least be able to adjust the tension of the others to compensate for broken ones. Lastly, carry a few spare parts: tubes (duh), one or two tires (blowouts can be fairly catastrophic -- not something a little duct tape can fix), extra spokes, brake pads, and cables (for brakes and gears).
Here are a few shameless propaganda photos to convince you cycle touring is cool:
Here are trip reports of the three long cycle trips I've done:
Here's some info about making your own cycling and camping gear: