honestly i think that riding on the sidewalk is super dangerous. if you're only going 5-8mph i assume that would be actually pretty fine. I mean, YMMV, but as long as you are very observant of pedestrians, you might be fine.

the thing about roads is that there are well defined rules which creates a highly predictable atmosphere.

riding with pedestrians is very unpredictable. nobody expects to encounter a bicycle moving at a high rate of speed when they cross a bike path. (duh!) people don't look both ways when crossing bike paths. they stop dead in their tracks. they stand on teh wrong side of the path. it's scary becuase you don't know which way they will move to get out of your way. sidewalks are even worse because unless you are a kid you're basically not supposed to operate a vehicle on there. i guess that it is location specific, but sidewalks would typically have lots of telephone polls, pedestrians coming out of doors, thin sections if you had to pass somebody.

anyway if you are serious about vehicular cycling, then riding on the road is the best way to go. somebody like me who relies on my bike to get from point to point simply can not stay alive if i am forced off road onto sidewalks. I'd kill somebody or somebody would kill me.