I've not played Riverview, but I had a fairly simple, and very effective method I found for Sunset Valley.
There is typically some city event once a week or so - an Eating Contest, Chess Tournament, Neighborhood Grill-a-thon, etc. I found that by looking for those events, and sending my guitarist to arrive about an hour before they start with a full belly, freshly showered and napped, she could stand there and play for tips throughout the day/night and usually came home with six figures. I think it's the events that draw the crowds, not necessarily the venues (although I'm sure some venues receive more visitors than others). Naturally, the guitarist spent the rest of her time performing at home...
It might be worth a try in Riverview.