I moved to Ocean Beach when I was a kid in the 70's. We live/lived right around the corner from where the ice rink used to be. I found some older friends in the neighborhood almost right away and they would take me ice-skating every Sunday night (I'm pretty sure it was Sun.). I got a pair of refurbished skates from the rink for a birthday present one year, I remember. And I always had my birthday there!
I have to say, living here still and raising my own kids now, I wouldn't pick any other part of the city. There's so much wide open space for kids.
And really, it's not that run down. Maybe the 7/11 isn't great (but when was a late night convenience store great?) but there is Java Beach. And do you remember how seedy Kelly's Cove used to get on a hot day?
I must agree that the bums have changed somewhat for the worse. When I was a kid I used to trapse over into the sand dunes with my friends and sit around a fire with some of the old winos out here. The steaks they grilled were great. (What was my mother thinking letting a ten year old do that?) But the old guys were always very protective and kept their bottles away from us and sent us home before midnight.
I think you have to have some backbone to want to be homeless and camp in this windswept, foggy part of San Francisco.