I gotta say,there's a LOT of ground you could go into.

What appeals to you? Is this something you want to do immediately, or something you can ease into? Does it need to be lucrative, or can it be a bit more frivolous? What other skills do you have?

Also, what do you define as 'rewarding'? It takes a lot of education, but teaching is usually a very rewarding pursuit. If you're young and in good enough shape, law enforcement may be an option. If you're interested, there are quite literally thousands of options available in the medical field - some of which your prior training may be useful for (medical equipment maintenance, software and database wrangling, that sort of thing).

Again, if you've got the wherewithal to afford it, you could also look at various forestry positions - and as our dear Chanteyranger proves, sometimes that even leads to music! (He's in charge of the Hyde St. Pier shanty sings in San Francisco - held in the Hyde St. Pier Maritime park, aboard one of the ships there).

If you're serious about a complete change of career, and have the money for it, this could be something that very few people ever get the chance to do. Just go into it with eyes wide open, and brain fully engaged.

M