Also coming in late, Barb - my apologies.
I'd second the opinion of most here that no formal classes are necessary. What is, however, almost essential, is the
guidance of a genuine historian. You're right to suggest most won't have the time to do your research for you (nor would you want it) but if you go to them with specific questions, eg 'which out of the following books are the best on this one particular small issue?' or 'I've heard/read this anecdote, is that something worth following up?' they will usually be absolutely delighted to help - and thrilled at your interest. The crucial thing is to do a lot of research on your own first, so you can prove to them you're serious about what you're doing.
I'm doing mid 17th century France. What I did was pick the books I found most helpful in the early stages, check out the author biogs, find their e-mail addresses on their respective university websites - then just write and ask to meet them. Everyone so far has responded brilliantly, and I don't know what I'd have done without their help.
Something else you should ask them to do for you is get you on the H-France list. This is the e-mail forum for members of the Society for French Historical Studies, and I have found it invaluable. There are other fiction writers who occasionally ask a question there, and though it's frowned on for anyone to ask too many questions, the reviews will keep you up to date with research in your field and there are any number of helpful links constantly being posted for other members to see. It will also help you identify other victims you might want to write to off-list to help with specific questions. To join H-France you will need sponsorship by an academic member - which is where again you need that all-important first historian mentor. One also leads to another - when you write to someone else, it's a great help if you can say 'I was recommended to you by Professor X at Y'.
In terms of French - yes, there's no doubt it's a great help, as many of the good sources are only in French. It can be done, though - I've just plodded though the whole of the Mercure Francois 'History of Our Times' for 1641 (mercifully digitized online, God bless Leicester University) armed with only a pocket dictionary, and it's surprising how quickly you get the hang of it.
Have you found
EuroDocs yet, by the way? There are a few good sources there, and some are translated.
Yours is a great period. If you ever want to indulge in mutual brain-picking, do give me a shout.
Best of luck,
Louise