Also, the scareactors will NOT touch you. They are allowed to get in your face and space, but that's about it. Likewise, you should not touch them.
Photographing scareactors in the streets is permissible, and is Strictly Forbidden in haunted houses. If you take pictures inside a haunted house, you'll be pulled to the side by security and may be asked to delete all the pictures. The no flash pictures requirement inside houses is for the safety of the scareactors, other guests, and safety TMs stationed in the house.
Food and drink are permissible in haunted house queues--there are often little bars selling bottled beer, soda, and water in the queues themselves--but must be finished before entering the haunted house. You will be pulled aside and given a chance to finish if you haven't already.
Open containers, including souvenir cups must be empty, turned off (if they're the flashy type) and stored in a pocket or purse before entering a haunted house. All flashy stuff must be turned off before entering a haunted house.
Alcohol is sold EVERYWHERE. Most places that sell alcohol will also have non-alcoholic options available. Expect to see a lot of drunk people. Don't worry, there is also a lot of security available, and OPD is always on-site.
Skip the first Bill & Ted show of the night. This gives you more time to see haunted houses with lower waits.
Most of the restaurants and gift shops will remain open. These are also "safe zones" if you need to avoid scareactors.
Rip Ride Rockit will probably close its line earlier than the posted park closing time (11-1130pm on a midnight close, midnight on a 1am close, 1am on a 2am close). So if you want to ride it at night, keep this in mind. As long as you are in the line for a ride/haunted house before they close the line, you will get to ride/walk through. Once a line is closed, that's it.
Express passes for HHN are available, and frequently sell out. If you get there early, tour opposite of the crowd flow, and skip the first Bill & Ted show, it is possible to see all the haunted houses by 1030pm without needing Express.
Only HHN Express is valid for HHN. Onsite-hotel room keys are not valid. Studio Express is not valid. VIP express is not valid. GKTW/Make-a-wish must see Guest Services for a HHN pass (if available).