Hi Jenn, and welcome to Pet Talk! There are a few people here who will be able to help you much more than I can. One in particular, K & L, has extensive experience in trap, neuter and return. Her and her husband take care of a park full of TNR cats in Arizona. I've PM'd her with the link to this thread, so hopefully she will pop in soon.

Others have done extensive rescue, Queenscoopalot, Kimlovescats, Leslie, Moosmom, JenLuckenbach are just a few that come to mind off the top of my head.

I've never done anything like you are going to attempt, but from what I understand it's a tough job, but it's so rewarding when you start to see the fruits of your labors - which is when you have a spring come and go with no new kittens. You will have many emotional ups and downs, but if you stick around here, there is a great support network that will boost you when you're down, and celebrate with you when you're up.

Good luck, and please let us know how it all goes.