Improving when swimming alone

This is my first time to this site; it's excellent! I wish I had more time to really surf it. I'm a recreational swimmer in my late 30's. I swim two mornings during the week, and on either Saturday or Sunday. Due to my work schedule, and the fact that I swim in the morning, I can only allot approx. 30 minutes. So what I've been doing is swimming a mile of free non-stop, usually finishing up with a sprint for the last 80 (it's a small college pool, 20 yards). I want to change up my workout, but there's no Masters group or adult swim group locally, and I don't have the drive to actually GO somewhere that has them (the pool is walking distance from my house). My questions are: 1. I do a VERY poor butterfly, but I don't know how to correct it without getting some coaching. How does one get coached in swimming (or improve his stroke by reading "how-to' articles) if there aren't any local groups that cater to adults (that I know of--I live in Frederick, MD if anyone knows of someone), and I can't see what my stroke looks like. 2. Is there a recommended 30 minute "fitness" swim workout that you could direct me to? Periodically, on Saturdays, I'll swim about 2500 by 400's, then 300's, etc., each of free, ***, back and free again (where it WOULD be fly). 3. What's the deal with fins and hand paddles? When are these used? Any help you can give would be appreciated. Until then, it's "TS" for me! (Simpsons reference)