We are considering going to Bath before our London tour - the timing is the Jane Austen Festival, is that a bad time? I don't want the crowds, but it might be fun too - has anyone been?
This thread from March may help you:-
https://community.ricksteves.com/travel-forum/england/bath-and-the-jane-austen-festival
I was the one that started the thread Nigel linked to. I love Regency era fiction and am looking forward to this. Here is a link to the program/programme for the festival in case you are either interested in doing or avoiding! I have booked a couple of the events as I have no idea whether they fill or not.
http://www.janeaustenfestivalbath.co.uk/2015programme/
Are you planning a day trip or are you going to spend the night? Do be aware that even on a non-event weekend many of the lodgings in Bath have a 2 night minimum for Fri/Sat.