Now having floated the possibility, I now feel bad for doing so. I'll explain.
The Scottish Rite Auditorium has a season, i.e., they don't hold concerts year-round. It temporarily slipped my mind when I suggested it earlier. They don't have concerts during June, July, and August. Their concert season runs from September to May. So, we're going to end up with the Sunday/Monday 12th/13th pairing at the Keswick (or shows after their Tarrytown show on the 19th) or they will play somewhere else.
I was thinking other places in Philly that could host them. The relatively new venue, The Fillmore, could definitely work too. Yes played their two "50th Anniversary" shows there (and they had their 50th Anniversary celebration before the concert in a nice room upstairs). It's about the same size audience-wise as the Keswick and Scottish Rite.
I suppose they could also play shows at the Keswick before or after their two shows in Quebec City in September (I wonder why those two shows are all alone for now). I just don't think that they would want a six-day break in mid-June; that's a lot of daily fixed costs accumulating without money coming in.
Well, I hope we find out soon.