I don't really have advice, but I know there is a very large number of people in their 40s looking to change careers so probably there are many common pathways, internet discussion forums about different professions, etc.

Same for people in the 30s. For example, in the lower ranked medical schools in this country (US), there are many former programmers in their 30s, and they discuss things on boards like http://www.oldpremeds.org/phpBB3/