I have the same issue... I live in a really crowded built up place and there just is not much in the way of places for dogs to 'be' off leash.
The closest I get is a several acre off leash dog beach and a national forest, unfortunately they are both a bit of a drive away.
Would something like a preserve or a national forest nearby work? When I take them up in the mountains they have tons of space to run and hardly anyone there. Possibly a large fenced in area(possibly dog park) where you can work on some recall and kind of see how he does off leash first.
~Ollie vom Grunenfeld HIC(8/29/2012)WGSL/WGWL/DDR cross - herding dog in training!