I thought I would update after our holiday last year!
Biggest advice: October is the start of winter opening hours (forgot that from last trip to Vancouver) so quite a few places either weren't open (eg the theme park, apart from late night Hallowe'en events) or had different opening hours.
We spent a week in Toronto, and loved it. We bought a CityPass which was a small saving for attractions. From that pass, we went up the CN Tower (cracking views! Kids loved the gift shop), got the boat to the islands and walked around there (cracking views back to the city). Also went to the Ripley's illusions place which was good for a few hours when the weather was a bit grim. The zoo was excellent and the aquarium at the bottom of the tower was a lot better than we all expected. Also went to the museum (i LOVED it).
We walked everywhere and found good lunch places on our last day in the train station!
There's a place at Roundhouse Park at the bottom of the CN Tower that has a lot of old train carriages and a wee ride on train (we didn't go on that). Nice place to chill. Also enjoyed Berczy park with a fountain decorated in statues of dogs.
Eaton Square Shopping centre had a foodhall and range of shops. We walked a lot between the shore to Eaton Sq and up to the university and all over.
Didn't get tickets for baseball or hockey but watched them in bars or restaurants.
Loved St Lawrence Market - upper level food places were great. Lower level had mix of wee shops and food. Went there a few times.
Favourite place of all was the Distillery Quarter. Shops, cafes and a few restaurants. V chill and great photos.
We got a Flix Bus to St Catherines which was easy. Stayed there 3 nights and went to Niagara Falls on two days. Went on a boat (got soaked, epic!) And behind the falls. Also went to Clifton Hill and played indoor crazy golf and went in an illusion/hall of mirrors that was more fun than expected too. And then a day at the outlet mall where we bought clothes, shoes, etc and felt smug about saving money.
Flixbus back to Toronto and then the train to Montreal. Prices were reasonable for both, I think about $200 for 4 return tickets on each? Can't remember but reasonable anyway.
We stayed on the edge of China Town in Montreal. First day went into the old town and wandered about. We hadn't expected a culture shock, but everything everywhere was French. It was genuinely like being in France! Anyway, enjoyed that wander. Next day we got the subway to St Helen's Island and walked about there. It was shut! But getting decorated for Hallowe'en. We saw an Otter! Just trundling around.
Complex Desjardins shopping centre had a great foodhall. We went a few times. We walked loads again. Walked to McGill University and spent an hour or so in the wee museum there (it had a dinosaur!). Also went to the planetarium. It was a great city to walk around.
We loved Toronto. Loved how it was a living city- loads of playparks in amongst the skyscrapers and so many dogs out and about!
Using the train and the coach were great as driving and parking were expensive and we didn't want the hassle.
Using our phones was expensive. We didn't buy sim cards there as we thought we would be ok. WiFi was pretty decent everywhere but if we used 5g it was so expensive.
Thank you for all the ideas and suggestions. If we go to the east coast again we would explore away from the city so all those places like algonquin are still on the long list.
Happy to give details of where we stayed and ate (and if we would recommend!) If helpful to anyone.