Going by my experiences at the wonderful Manchester Gathering, it seems to me that one day probably isn't enough - if people are travelling a long way, they'll probably want to stay a couple of nights, which means Friday Night and Sunday lunch time as well.
We put a lot of thought into this, thinking at first that a different venue for each session would be a possibility, but in the end we agreed that all the sessions would have to be in the same place - to avoid confusion, to make it simpler for people booking B&Bs, only one landlord to 'sweet-talk' first....
Just my tuppence worth.....
Cheers,
Catrin