What is the rule if you hit a cartpath sign in the fairway?

Answer 1

You mark where the ball would lie if it was on the ground, lift it, move the cart and then drop the ball as close to where it would be as if it was on the ground. This is a free drop.

Answer 2

If your ball lands on the fairway or in bounds, there is no penalty for hitting a cartpath or any other sign. You have to play the ball where it lies just like if you hit a boulder or tree.