1. most clubs do allow spectators to follow along. You may want to ask before hand though.
2. as far as your set up goes, you should be fine. If you are just looking to shoot for the fun of it, you can shoot from whatever stake you feel comfortable from. You may want to explain this to the folks running the shoot. Your equiptment may put you in a more competitive class. There are a lot of people that may question where you are shooting from, but as long as you don't turn your score card in, they shouldn't have a problem with it. Using your target set up, you may also want to take a range finder along with you, since you maybe shooting slower than most 3D ers. No since in losing arrows if you don't need to.
3. good luck and enjoy.