Personally I have ridden up in the jump plane before when I was in the early stages of my IAD jumps, it was fun seeing jumpers from the King Air instead of the Cessna, which was what I was used to. Your friends/family should enjoy watching from the ground just as much as the air if not more because they get to see you under canopy and on your landing pattern.
As far as gear is concerned I agree with what everyone else has said, BUT I would give you the advice I was given as soon as I graduated IAD student status. The first things I bought was a helmet, goggles, and altimeter. Don't get me wrong, you are able to rent these along with your rig until you buy one, but having a helmet, goggles and altimeter might make you more comfortable like it has for me. I would say don't throw down STACKS on that gear, but personally having that gear has helped me become more comfortable and consistent.