Matt,
We could be married to the same woman!
My wife is working now, but in another year or so would love to start her own gig, doing books from home. I think the key is, like anything else, to build a contact base in the meantime. Then plan a dateto start. Inform the contacts and have a few set up as charter clients. Start small, and then grow it.
She could even try doing some part-time after her normal work hours. My wife has done a bit of freelance like this in the past for some small companies. Set up their books, manage them and get them rolling.
It's a lot of work, has to be worth it in the long run.
Good luck!
Randy