The riverside reconstruction of Hudson's Bay Company's log fort gives you a glimpse into life in a trading post in the 1840s, right down to the smell of tanned hides. To reach it, pass by a 1920s midway and farm, and a few blocks of Edmonton in the 1920s, 1905 and 1885. Hop on a street car or horse carriage, chat with 'locals' (employees dressed up from the relevant era), do some yesteryear shopping or try the penny arcade.
You'll find an ice-cream parlor, bakery and cafes, or dine at Johnson's Cafe (dishes $6 to $18) at the Selkirk Hotel, where you'll find gluten-free options that weren't likely available in the 1920s. There are plenty of shaded gardens and playgrounds. If you've got kids in tow, be sure to check out the upstairs playroom in the MacDonald House with toys you can try out from 1885.
Note that the park is closed for general events the entire 2019 season, possibly later, for renovations. It still has special events.