Those old Schwinn frames are heavy as ****. Crush or no crush, I think you ought to at least inform her of where she's about to end up and what could be done to make it work out much more desirably.
Find a garage sale ten speed bike with three-piece cranks. Pick up that Mavic CXP22/Formula wheelset for $130 or so and scare up a cog, lockring, and chain. Pretty much good to go.
Originally Posted by slopvehicle
Interesting-- the rear wheel is a sort of multi-gear fixed hub?
Yes and no. I disassembled a trashed FFW bike a few months ago for scrap steel. It uses pretty much a standard one-piece steel crank, but the chainring that attaches to it has a set of bearings and a ratchet built into it, so you literally have a huge freewheel attached to your crank.
The rear sprockets are a stack of cogs sandwiched together with spacers between them. The hub-like thing they are all slid onto has teeth machined into it and each sprocket in the cluster has a very simple ratchet mechanism (a spring and a small block of metal to drop into the grooves on the shaft). Basically, the cogs on the rear hub can freewheel, but it takes a bit of force to get them to do so. This is apparently so you won't die if your shoelace or cuff gets in the moving chain.
I actually took the frame and BB/crankset from this bike out one night while drinking, and made it into a FFW singlespeed just for the hell of it. I had a ghetto 27" wheel with a suicide fixie hub and stuck some bars and a brake on it. You could coast going down the road, but the chain keeps moving and the chainring freewheels with a very loud clacking sound. I think I still have the frame in the garage somewhere. I should put it back together like this some time.