Thanks for all your thoughts... I'm likin' the anchor bolts. Also, the equivalent of REI up here (MEC) has a case-hardened chain for only 37.00 - could possibly wrap it around the lone tree and leave it in place. It's amazing how utterly sterile this place is. We share the parking lot with the local DMV testing station and sinking a bolt into concrete would probably involve many layers of bureaucracy. They're in a cinder-block building with a gas meter - I'll ask. Considering this place is about two miles from the nearest bus stop, I'm amazed no one seems to bike here.