Just a tip. If you're making a structure make sure that it's structurally sound. Dig deep and cement that sucker into the ground real nice. In addition you'll probably want to make "collars" for your posts (AKA "post wraps") which direct water away from the post when it rains which not only prevents it from rotting faster but also keeps the soil that's around the post free of as much moisture as possible so that it doesn't turn into mud and start falling over.
This is a perfect example of a collar except for the fact that it's straight and not angled so water may pool up, make sure that the water gets directed away and not pooled up on the collar itself.
EDIT: Forgot to put the image http://www.mailboxesofchoice.com/Ima...llar_Small.jpg
@ OP: Actually it kind of does sound like you put some thought into it but I'm willing to say probably not enough thought, you'll need more than just willpower to take on something like this, heck I thought I was going to make a stupid table in 3 days but it ended up taking a week and a half mostly because I was clueless, and didn't have a solid plan (sure I had measurements, made my cuts precise and such but no such plan for what was going to happen "in the middle portion" of making that table). You're probably going to want to think about starting off with a few smaller structures first then working your way up to a major project.