Like previous reviewers have said, the beach shack is truly just that--a shack. It is very, very small. The bed is very comfortable, but the bathroom is incredibly cramped--I mean if you sit on the toilet, your knees will knock the sink. We brushed our teeth and washed our face in the kitchen sink rather than the bathroom. If only you could swap out the kitchen for a larger bathroom!
The shack is in close proximity to Ocean Beach, but it's not truly a 1/2 block from the beach. The end of the street was closed during our stay, but even that would've led to an overlook and not the beach itself, so we walked about 5-10 min down some nearby streets to the actual beach.
It was rainy our first day there, but did clear up--we found the room very, very damp and humid. Entry into the room can be difficult your first several times. We also had a small problem where the WiFi password on our provided information was incorrect, but after exchanging a few emails with Doug, it was sorted out.
To be totally honest, the shack was fine for the short stay and if you plan on only sleeping in your room (and I mean that, if you're someone who needs space to get ready before going out, good luck!). Ocean Beach was our least favorite of all the ones we went to. In the future, should we return to San Diego, we will stay elsewhere with a better location and slightly better size. If you're okay with something more spartan, this might work for you.