would you ever try to make something resembling a car / cart?

I was taught they never actually lived in caves, by an angry frenchman when I visited caves in France. The car sized bears did hibernate there though (and people did paintings in the caves).

But if you knew what you knew now you could do a lot. Just knowing that you can bake mud to make clay. Getting running water to where you live could be a game changer. It's the key to agriculture, sanitation, etc.

Weapons are the same. Knowing something like the bow and arrow is possible will put you way ahead of sharp sticks and rocks.