> how much of my time should I expect to be spending indoors vs. outdoors?

That's a bit like asking "How long is a piece of string",since you haven't said what you intend to be doing Ivy - so it's difficult to make any real comment. There are usually over 700 official events, not to mention all the unofficial stuff,both indoors and outdoors, so it's really up to you how much time you spend exposed to the elements or not. It may also make a difference if you're intending to be whizzing around to different venues in the town, or staying put in one place.
Impossible to answer :-)