I would drive to the suburbs. Penn Wynne courts are usually available and not a bad drive but really there are courts all over Lower Merion.

The smaller courts in Center City are busy and if you can’t reliably get on the court right away it is worth an extra 10-15 minute drive.

The courts at FDR are the exception, usually not a bad wait, but not a sure thing at prime hours. Strawberry Mansion is usually free too but not a great area. Fairmount Park-Chamounix courts are always available but bad quality and almost as far as the suburbs. The courts at Allens Ln and Water Tower Park are also decent for availability but even farther from CC than the suburbs.