@Susan234, look up the venues via ticket sales, they are using central city cinemas, I think, and write to some hosts whom you think are in a reasonable locality for your needs and ask them about the transport and travel to the Open Events, they can give you local on the ground info as well as an indication of travel costs. In my case I factored travel costs in and opted for closer accommodation.
There is no one size fits all answer to what accommodation locality will float your particular boat.
Test the waters with a few host enquiries.
best regards, Christine