If you have a close friend who would like to marry you they can get ordained on the internet (
http://www.universalministries.com/doctrine.cfm is the first paid link from google) and can usually perform the ceremony. Check with your local courthouse.
My wife is a caterer, she often plans 5+ weddings on a single weekend in the summer so we knew ahead of time where we were doing it, who was catering, what we were doing for flowers. A friend is a pastry chef and did the cake, another friend is a pro photographer and took care of pictures. From her experience she knew what she wanted for music. We started planning a year ahead, but it was mostly just letting our friends know when the date was.
The main reason to start planning in advance is because some places book up. My wife's company is already booked for two weekends next summer.