Re: 20 Inch Occ Schwinn Stringray 5 Speed?
The only 5 speed internal gear hubs I'm aware of are the old dual lever Sturmey Archer and the Sachs with the click box.
For simplicity, I'd use an axle mounted derailleur. It's much cheaper too.
“You're only young once, but you can be immature as long as you like" -Unknown