Yes. Yes it is.
Matt, while it is true that most of the stores are pretty similar, they do vary in size. I am not really familiar with the Toronto stores.
The London store is nice, but not the biggest. (Now Halifax, THAT was a big one. So was the Ottawa store, for some reason... :p)
But the bonus, in all the stores, is the "markdown" shelves. They always have a small section where returned, damaged, or discontinued stock is marked down. You never know what you'll find there.
Another thought is to check the Lee Valley Seminar list -- which varies completely by store. Maybe you can find a seminar that you'd like to attend on the weekend you visit. Some are all day, but some are just a few hours.
If you stop by the London store, you can head west from the store a mile or two and look for "Federated Tool" on the south side of the road. It's a pretty nice tool store. Dave Eisen is one of the sales guys there and is a SMC member, though not too active lately. Not sure you'd find any deals there compared to back home, but you might enjoy the browse.
If you want to spend the night in London, I suggest you check out the Best Western Lamplighter -- I've never been there myself, but I know that it has a huge glassed in atrium with indoor pool and one waterslide, which LOYLjr might appreciate.
In Toronto, your daughter would probably enjoy a visit to the Ontario Science Center, Or the Toronto Zoo (be prepared for a lot of walking, it's huge.). I've also heard very good things about the Canadian Warplane Museum which is in Hamilton area. You probably already know all about what's at Niagara Falls. (The Great Wolf Lodge there is bigger than the one in Sandusky, just FYI.)
Have fun. Any other questions, just drop me a PM!
...art