Gay Parent Support Groups
The first order of business is to let others know you exist. I would start by putting an ad in the local paper saying "Gay dads looking for other LGBT parents." You can give a cell phone number or an e-mail address. Are there other local parenting type groups (playgroups, "parent and baby" groups)? You can let them know that you exist, and ask if you can put a small announcement in their newsletters, or ask to join them.
You can also put up small notices in the local supermarkets, ice cream stores or coffee shops. A college campus may have an LGBT group, although students are less likely to be parents. Organizations like Family Pride can help you get connected to local support groups.
Part of what you are trying to do is start a breadcrumb trail or weave a spider web of connections. You need to let people know that you exist, and then someone will know someone who will know someone else, and that's how you will get connected. LGBT parents are everywhere, just like you. My guess is that some other families are out there looking just as hard for you as you are looking for them.