We would always "infiltrate" the "enemy base", which was this county place down the road where they kept all of the big trucks and snowplows. There's no fence around it, no guards or anything. Crime/vandalism simply wasn't a problem in my little town. We would just sneak around, take out sentries, get the data on the enemy missiles, plant the charges, and escape into the night.
Other times, there was this ruined mine building foundation that we would often go to to rescue prisoners.
Good times, my friends. 22 may seem young to feel nostaligic, but I miss those days sometimes.