Dan,
A park is fine for the Firebirds, but be sure you are well away from people and any buildings. The Firebird will need the equivalent of at least two soccer fields of area without obstructions. (Like trees, poles, dogs, etc.
)
Do NOT try to fly when there's more than a mild breeze. If you see tree branches moving, it's almost too windy for the Firebird. [:@]
Bring Foam Safe CA (usually "odorless" CA) or 5 minute epoxy. You will most likely crash repeatedly, and glue may keep you flying. 5 minute epoxy will usually cure enough to fly again within about 30 minutes. Foam safe CA cures almost instantly.
AMA insurance is a good thing, but probably not necessary for your planes. Of course, if you fly around people or buildings and hit someone or something, you could be sued.
As James said; use the feature here at RCU to locate clubs nearby. It's worth driving by to watch and ask questions if nothing else.
The AMA site also has a club locator page.
http://www.modelaircraft.org
Best of luck,
Dennis-