What would happen

That sounds like me until I was 10 years old, with no electricity until I was 5. Bedtime was early. We did have radio, but it was rationed. Batteries were expensive. We played cards, chess, checkers.. read books. Most of the time we were either sleeping or working...

Looking for critters or rocks. Skipping rocks on the water. Looking at new plants they never saw. Enjoying the view of whatever is in front of them. Build a fire. Cook on the fire. Tell stories about childhood or family members who have passed. Go for walks. If there were other people around they might get to know them and tell stories with them.

The Amish do that. But part of what makes it fulfilling is the sense of community with other Amish families.

Board games
Hobbies/art&crafts
Talking
Exercise
Outside activities

The way we used to - with imagination and creativity.

All these devices are killing our ability to think beyond what we feed our eyes.

Once, imagination was all one needed to play, to create, to discover.

They would probably take up other hobbies. Probably make trips to the library to pick up books. Likely a lot of day to day toil to provide for themselves unless they still work in the modern world and just don't live in it.

Where's the cabin? Why would they be there? Is there running water? Is the heating needed and if yes then what is the method of the heating? Adults would spend a lot of time preparing food and taking care of stuff like heating if needed. Kids would be engaged with any activity they'd find interesting. Playing with their toys, drawing, running around..

Playing games, doing chores and enjoying one another.

Reading books and talking to each other.

Meaningfully

Make firewood and hunt

Fishing hunting and riding 4 wheelers

Invent their own entertainments and hobbies, mainly. Read. Play musical instruments.

After all, that lack of gadgets was reality for most people only fifty or so years ago!

Weeping bitter tears.

Fishing, swimming, camping, board games

Hard to say James, maybe they would start living the way people used to.

Woman would choose household chores.
Kids would play with each other.
And Man would go to coal mines.

Go fishing to get dinner, have a fire going, explore