If you are hoping/planning/wanting to serve champagne or any other type of alcohol at the reception, you might want to check with the church and/or the park staff to see if it is okay. For exapmle, I know that our church doesn't allow any alcohol in the building (heck, we even use grape juice for communion!
) and I know that there are some parks where alcohol isn't permitted too. Wouldn't want you to get in trouble and/or purchase some nice bubbly that you then can't use! Of course, we're United Methodist and you mentioned the church is Episcopalian, so you might be all right anyhow.
Even if you don't go for a whole catering thing, you could probably get some tasty trays of cookies etc from a bakery to jazz up the reception a bit and still cost less than a whole big meal...... Who doesn't like cookies?
Cheers!
Heather