To be clear, you are referring to Buck Sansom Park where the shooting's going on, not Marion Sansom Park, off of Robert's Cut Off, where a pretty good mountain bike trail is maintained. Marion Sansom Park is relatively safe., and located only a mile or so from the end of the Trinity Trail.

You might try parking where the trail runs under North Side Drive, or at the FW Cats stadium - never seen/heard any issues there. You could also hit it from Gateway Park, on the East Side.