Where I live, there are a fair amount of the halfway house types that hang around the rail-trail, b/c it runs thru the downtown city park.

I'm not sure they are entirely harmless, but most I think are just old alcoholics and half-brain-fried vagrants who have lost their sense of what is socially appropriate. (Like staring directly at you, or broaching the personal space bubble -- or staring at your a$$) I think that lack of social awareness and propriety is what makes them seem even scarier than they are. There are also a few old guys who ride the trail on old bikes with their knees stuck out like you describe - maybe even with their groceries stuffed in a sack - cause it's the best way to get across town.

The guy you had a problem with may indeed have been a drunk -- lost his license and his car over the years, so a bike or his feet are his options. So a guy with no social awareness .. on a BIKE... in TRAFFIC..... near YOU.... and WITH your husband.... has got to be a REAL freak-out!

I sympathize - he'd have given me the creeps too.