My thinking is to get two more OCC rear wheels and mount 5" wide Harley tires. I had a pair of these, but just got rid of them because they wouldn't work with brakes and chains, but on the trike I don't have to worry about that.
The trike has a single speed coaster brake hub with another gear on the other side. I am going to half to take a look at how that other gear is attached. I would love to replace the old hub with an old SA 3 speed hub. That way I can have the gearing, but also a cool stick shift.
I don't expect to start building on this anytime soon. Just thinking out my options and start collecting parts and ideas.