"I've looked into that angle too, after several people recommended substitute teaching. I discovered that out here in Kansas City you need to have a state teaching certificate to serve as a substitute. There might be a poor school district around town that doesn't require a teaching certification, but I haven't looked too comprehensively."
In California, you just need to pass the CBEST (a literacy test) to substitute teach. Also, here, there are 1 year teaching credential programs (Hawyward State) that let you do your student teaching while you are in the program. So, in one year, you're done. Lots of teachers are retiring.
Joanna