Cal was put in the hospital when he was sixteen (almost seventeen) and got out just after he turned eighteen, so he's been out of there for nearly five years. The only real job he's been able to get has been as a janitor, though, since he's not college-educated and he's got his diagnosis on his record.
As for visitors stopping by, Cal definitely wouldn't object! He's really friendly, he just doesn't have a lot of friends, mostly because people find hime kind of weird, so he'd probably love to see Edward again :)