Oh i know some other activities like:
-craft something made out on nature like chestnuts and acorns (to name 2 things)
Make some kind of soup you either have found or have buyed them
Create some kind of recept
Have a cookbook so you can learn new things you can cook
A new skill very similar to painting skill (or expand the painting skill) you get your hands dirty and a option to paint them on the walls and maybe even floors (the latter it's similar to San Myshuno) and of course paint some items like chestnuts and acorn (to name 2 things)
Create some kind of decorations to fill the house a bit
Create a fall bucketlist (similar to "Life and Death" except it's exclusive to this pack idea only)
A thanksgiving kind of party you can throw
A pumpkins painting events
A fall festival events
A pie bake off events
You can have a new collections with fall natures like i mentioned from above (chestnuts and acorns but there's more of course) leaves, feathers etc
Making candles with this new skill
Everything related to pumpkins (like crafting pumpkins, making pumpkins soup etc) literally everything related to pumpkins
More orange, yellow, red and brown furnitures, walls, doors and floors options with a fall themed pack
Similar to Henford-On-Bagley you can visit a small farm market to buy the ingredients you need either for craftings things or to cook some new things (with a cookbook if necessary)
I came up with these things
Not activities related but we need a cozy backyard too
With a new world the daylight starts later than the rest of the worlds and gets darker earlier than the rest of the worlds (the climate may not be possible if Seasons isn't installed but it should still be possible to have a weaker daylight than the rest of the worlds even without seasons)