Pine River is a good solid field. I've played there for a few open dates and one reserved party, with another coming next month.
The shining jewel here is an 11 acre woodsball field. There is plenty of cover - some natural, some built. There's a cabin and a bridge, a long ridge, a river, some long grass, and plent y of space to move. CTF and team elimination games start out of sight from each other, so you never know where folks are gonna be. The staff have a large list of games they'll call for you, from CTF to Rescue the Dummy. The open field allows plenty of room for advanced maneuvering, flanking and sneaking.
The field staff is knowledgable and helpful. The owner and his sons are great at keeping things moving, keeping things safe, and helping players out. They have a dedicated chrono/target shooting area, which is highly welcome.
Safety is big here. The playing area is separated from the staging area by a good distance. Tape is very prevalent in the out-of-bounds areas. Netting separates staging and chrono areas. The refs are very good about enforcing barrel plugs and masks.
Fills are reasonable and fast. This is a field paint only field, and the prices aren't great, but they're reasonable. The cheap balls work very well in my 98c. They give a safety lecture to newbies and an intro to the rental gear. This is great - other fields just hand you a marker and tell you to go to town.
Cons: On the woodsball field, head shots and gun shots don't count . This can be an issue with good players, as you could hang out and take gun shots all day and keep firing. I suspect that if we asked, we could suspend this rule. Also, the walk from the parking area to the staging area for woodsball is kinda long. Make sure you've got your gear packed well. If you try to just drag stuff, you'll have issues
They also have a speedball field, but I have yet to play on it.
All in all, this is a great woodsball field. I play here about every five or six weeks, and I'm always impressed. Even with the FPO restriction, I still consider it worthwhile.