Figure out what kind of distances you'll need to cover every day to get there and back within the timeframe of your choice and then get used to riding at least that far.

There's a touring subforum on BF -- great place to do some research.

Will you be bike camping as well, staying at hotels, or with relatives and friends? This will dictate what you'll want to bring with you. I imagine you'll at the very least need rack and panniers to carry stuff?

[check mapping...]

Ah, around 100 mi? Some tourers cover that in a day, otherwise, probably two days on the road, or three if you want to take it easy. Sounds like a great, reasonable, very attainable first stab at touring.