We pick up in any Hotel in Reykjavík area, just keep in mind due to regulations some streets downtown Reykjavik are to small for superjeeps in those cases we use bus stops for pick up.
You can cancel up to 24 hours in advance of the experience for a full refund.
We had such a good time with the Superjeep Tour group, that I wouldn't just recommend this specific tour, I would actually check out the other tours that they offer too.
All I would say is wrap up as warm as you can.