I'm letting him out now and then when he starts to approach batshit insane... So far, just for a few hours at a time, although sometimes he'll want back in more quickly. As winter approaches, I imagine that the briefer excursions will become the norm. He never goes far... To the end of my building seems to be his limit, and when I go out to retrieve him, he comes almost immediately when "called."
I suspect that he didn't make it a whole lot farther when he was gone for two weeks. What fun that must have been!