I commend you for getting you fella fixed. We live in the country too but I keep all my dogs fenced in. We have about 1 acre around the house fenced in for them. We are on a paved road and the cars go by pretty fast so I prefer to keep them fenced in.
I have 2 males one intact one fixed and the fixed one is the wanderer so its hard to tell how they will react.
Sounds like your neighbors are being very irresponsible in letting their bitch out when she is in season. I know my breeding female never left the house if I wasn't breeding her that cycle. If I was it was always very controlled. I still keep my male for stud service but my female is now a he\she as are all the rest of my crew.
My little male stud muffin is pretty laid back and only shows interest when appropriate or when the vet gets out the vinyl glove and cup.