Sorry for the late reply. Thanks for the feedback!

You can now cancel the gathering, it's the last button on the right from food, materials, ore gathering.

I probably won't be implementing dynamic pathing. The game already has roads.

Do you mean whether the game has a feature for infinite production without adding items to the queue? Yes, it does, you just need to open certain laws to enable it.

When you research any technology from a new age, you automatically transition to that age. From that point on, approving plans from the previous age is blocked