On the trailer thingy...the two most important things you need are new tires/wheels (available at Walmart, but measure them first, 4 lug or 5 lug, etc. about $30 each) and new wheel bearings if you are dragging this thing all the way to Chi-town from TX. Also, lights are really nice to have when it's dark and required in most states. Of course you need a tag, but that's usually pretty cheap. You can buy a new light kit at Wal Mart as well, about $25, but the new wheel bearings could be expensive ($100 installed) if you have to get the old ones pulled off at a garage, due to rust (if as you say, it has been sitting a while and might have been in salt water, ever)

But at $800 for a SC 17 with trailer, a pretty good deal, unless it's got holes in the hulls and the sails are trashed.

Spend at least an hour looking at: the hulls from underneeth, the trailer tires/wheels/lights, and the sails/mast. Be sure the mast is not bent or dented.

There are lots of sailing clubs in the Chicago area on the big lake, but find someone who has cat experience to help you get started.