Apparently, your weekend problem is that you do not like to be bothered by all the kids who come by your house looking to play with your son. By the tone of your letter, I assume that they come by your home unannounced. Don't blame your son or make him feel guilty about his peers' weekend visits. You might suggest to him that he could let his regular group of buddies know what his weekend plans are (if he knows them) before the weekend begins, perhaps on Friday night -- phone calls, emails or group Instant Messages would do the trick. You might also ask him to tell his friends to call before they come over to see if he can play with them. But that might produce an equal number of "rings" as "knocks"; you can decide which you prefer. You could also leave a big note on your door indicating where your son is and when he might be returning. If you leave a pencil, the kids can leave notes for your son rather than disturb you.
This situation is only a problem if you treat it as one. I would good-naturedly seek your son's assistance in reducing your need to run wind sprints back and forth to the door on weekends. I'm betting that you can both come up with some creative solutions. I'd also suggest that you try reframing and renaming this "problem" as a positive experience, a natural consequence of your son's social successes. And accept my pat on the back for having a home where kids feel welcomed. Thanks for writing and for being open to seeing things with "different eyes."