I've read stories about some of the hilarious stuff he did away from the cameras. If a kid wrote him a nice fan letter, he might show up at their house a few months later, carrying a suitcase, like he took the invitation to come see them if he was ever in town to actually stay with them for a few days, deadpan as heck. Then he'd let the family off the hook and take them out to dinner or whatever.
He must have pulled some great gags on castmates from all the shows he was on, too. About ten years or so ago, they had a "McHale's Navy" reunion, on Ernest Borgnine's birthday I think. Borgnine showed up in an ambulance van, in a wheelchair. The driver wheeled him inside, right up to Conway, who was stunned to see his old pal in such bad shape. After a couple minutes, Borgnine jumped out of the chair, and laughed like hell while he bear hugged Conway.
"I set you up! I finally got you back, Timmy!" Apparently everybody else was in on the gag.
