Apart from different teams' Old Timer's Day game in their stadia, there was for a time the nationally oriented Cracker Jack Old Timer's Classic (as seen above). I think it was played in Buffalo, but maybe other cities too — usually non-MLB parks that resonated with old-timey glory. I think you're right that it was scheduled around the All-Star Game. They also tried to differentiate it by making it at least a little bit more competitive than the team-based games. Older dudes appeared, but recently retired Johnny Bench-types tended to dominate the action. I don't remember how much they shortened the fences — presumably they did to some degree — but I also remember in what I think was the very first of these games, a rather old (75-ish?) Luke Applinng led off with a homer, and he didn't hit a whole lot of those in his actual career. I'm guessing that, even though it wasn't that big a national event, team's assumed that it kind of made their own OTD games seem redundant, because the local affairs started disappearing around the same time.