To a native-New Yorker, Rochester isn’t “upstate” which to me implies north of Albany but still in the eastern part of the state, or no further west than maybe Cooperstown/Glimmerglass. You’re in Western New York. It’s going to be helpful if you can offer a car. But I do think Rochester especially in the fall, and your upcoming sit isn’t quite fall, but close with great weather might attract someone. You are near a major university, so there are always parents who might want to visit their kids. And if the dogs can be left for a bit or if doggie daycare or a walker to releive sitters is an offer you can make, then there is a lot to see and do in your new city.
Just be careful about accepting sitters from Canada as there have been some challenges with border guards which you can read more about here: Challenges with Border Guards - RE the Laws - #174 by Marion