My acreage is part field, part woods (not too dense, but out of sight)
I have the Fi dog tracker. It’s gps but no shock. It worked great for me. We moved to a much smaller farm so my dog wasn’t used to being restricted to run. We have only 20 acres now. It works with an app on your phone. You can pit a perimeter around your property and it alerts you when the dog goes beyond. It pretty accurate. My dog has excellent recall also so that helps. As soon as I was alerted I would whistle and she came right back. Take a little bit for them to learn the boundaries but was well worth it.