Thanks for all the good suggestions. I feel like I will soon pull the tranny out and not attempt a fix on the frame. It has almost 70,000 miles, and was rebuilt about 17 years ago when I returned the bike to service after a 20 year rest. I'll either plug it with a piggy back plug like 8053 suggests, or JB weld a drain plug in it.
I also have a spare transmission that has been gone thru that I may put in it, but it does not have the kick start mechanism. It would be possible to take the kicker off one tranny and put on the spare, but I don't feel qualified to do that.