... doing the STP on an ice cream bike.
After lustfully dreaming about this for a while, I finally broke down and found out the price and plausibility of my dream tonight. It looks like it would be about $2000 or more just for a (new) bike itself. That's not too bad for a high-end bike. And there's a "vintage" one on eBay for $700, so the price isn't awful.
So now I feel that if I am serious, I should actually call one of these companies and inquire about the rationality of my plans. I suspect that they're designed for dawdling around town doing one to two miles per hour, which is a great idea, but would be a really really time-consuming way to travel two hundred miles. "Slower" is OK, where "slower" maps to "about 14 miles per hour", but I don't know how viable pushing up a tank of ice cream up the hills of Washington would be if even going down them is an Exciting And Painful Adventure(TM).
Hm. Still, it is a sweet idea.