I live in Brentwood, but not sure where the Bethel Church is. Is it off Granny White Pike? If so, one night you need to head to Joey's Pizza in Maryland Farms. Awesome NY style pizza. We carry out there a couple times a month. If Bethel Church is the one I am thinking of, Joey's is only about a 2 mile drive.
If you don't want to deal with traffic going back into Nashville on Friday night, head down into Franklin. Lots of good restaurants on Main Street. Check the website for Puckett's Grocery. They probably have a live band or songwriters night. Mickey Roo's BBQ on Hillsboro Road in Franklin is pretty good also and they usually have bands playing at night. There is a pretty good restaurant/bar in the Factory at Franklin also...Saffire.
You may also want to check out the Puckett in Leipers Fork, or Greens Grocery also in Leipers Fork.
If you go over to Nolensville check out Martin's BBQ. Great food there, but nothing else to do in Nolensville once dinner is done. At least in Franklin you can finish dinner and stroll Main Street.
You can do anything I mentioned here if you are under 21.
I'd offer to show you around Friday night, but I will be in Chattanooga on business for 4 days....
Good luck, and thanks for coming to Nashville for your service!