There`s something to be said for Cyclebum`s comment that schnazzy stuff would be easier to resell if you didn`t end up liking bike touring, but that could end up being a much bigger check than going budget the first time around. Look at your bank statement, then flip a coin if you`re still on the fence.

A few ways to cut expenses:
top of the list, use things you already have. It sounds like you already have a bike that you`re comfortable and confident with. Do you already have car camping gear? That`ll save you a bundle. If not, you might consider not camping. Warmshowers and Couchsurfing will probably be able to net you several nights stay on your route, if you shell out for a hotel on the other nights, your total outlay might not be too much. Also, not carrying camping gear would make it pretty easy to get along with just a big handlebar bag and a cheap rack trunk. As mentioned, "bike" clothes aren`t a necesity. In fact, many of us actually prefer clothes that weren`t intended for bicycling. If you do carry camping gear, a trailer is probably less expensive than racks and panniers. Do you need a stove? I do because I ain`t going nowhere until I get my coffee, but if you can do without that coffee, or can be sure you`ll always sleep within shouting distance of a gas station, you can save money, space, and weight by "going cold". Alcohol or solid fuel tablet stoves split the difference between white gas or butane stoves as far as cost, weight, and space goes. And you definitely can do without even the least expensive fancy cookset at REI or MEC. For sleeping bags and tents, remember that funcitonal is usually very cheap and more $$ mostly just reduces weight and bulk.

Unsolicited advice:
don`t worry too much about having perfect gear. Perfection doesn`t exist and most of us keep revising and evolving our methods and packing lists over time. Don`t put off going because (insert excuse here) isn`t right or you don`t know anybody to go with or you`re waiting for the next season to roll in. If you do that, you`ll never get beyond your driveway.