Lots and lots of training will help with recall. It is of the most difficult commands to master for the dog. But, as you can see from the testimonials, it can be done. Just takes a lot of time and patience and treats
We play in fenced parks/school yards as well. They will come when called. Maggie is excellent and comes 98% of the time and comes right to me. Susie takes her time. She stops if I say "Susie Come" and she's running away to see something or greet someone coming into the park. But she takes her own sweet time coming back to me and she doesn't always make it all the way back before turning and going back again to check whatever it is out. But, I am working on her with a 2 call rule. I call once, she stops. I call again and if she doesn't come, I go get her and put her on leash for 5 minutes, no playing. She's getting better.
We've also been working on something new. I have been letting them go outside by themselves to pee and potty at night. They run out the door, down the stairs to the side of our building, do their business and come when called. Generally, they have been coming back on their own right after peeing, but sometimes they stop to check out a smell or something but if I call, they come right up the stairs and inside. This is coming along and will take more time as I have to work with them to be reliable with NO distractions, then work with them when there are, say, people and other dogs around. We've only been doing this when it is late at night and there is no one around to distract them from their "business." Slow but steady training, raising the bar a little at a time.
The best way to work recall, I believe is slowly and in very small steps. If a dog does well for a while but then starts to not respond, you need to go back and start again from the beginning and go more slowly as you work with the dog. It takes a LONG time for a solid recall and a lot of work. No dog is going to be proficient at recall without a lot of work and constant practice.
Anyway, keep after it and your dog will get better and better.