Thank you for posting this strategy! If I don't have Stay & Scream but do have an Express Pass, would you still recommend starting in the NY area to line up early? Or does S&S stand for something different? Sorry I am new to HHN this year will be my first time, and I'm pretty unfamiliar with the Universal park layout too but plan on studying a map prior.
S&S does mean Stay & Scream. When the park closes at 5pm, all day guests either must exit the park or enter one of the designated S&S areas within the park to wait for the start of HHN. You can't enter a S&S area unless you're already in the park before 5pm (which requires regular park tickets for that day, an annual pass or a Scream Early ticket). Additionally, you have to scan your HHN ticket to enter a S&S area (which will have scanners at the controlled access points). As Team Members and security sweep the park of remaining guests after 5pm, those in S&S areas will be released at designated times to specific houses assigned to those S&S areas (although guests in S&S areas may remain in S&S areas until HHN opens for the night without getting in line or going into a house). The S&S areas are "holding pens" that are blocked off in certain sections - guests can roam around in the S&S areas, but can't leave, exit or wander elsewhere in the park until released to a house or the S&S area is broken down at the start of HHN.
There are three S&S areas this year (although arguably five the way it's configured):
(1) New York (Halloween & Spirits of the Coven) - which extends from Louie's to Gramercy Park as well as back to the Transformers show building. Access point is between Louie's and Starbucks.
(2) San Francisco (Horrors of Blumhouse) - covers the area around and behind Richters and across the street from the exit for Fast & Furious. Access point is streetside on the Chez Alcatraz side.
(3) & (4) Central Park & Simpsons Area (The Weeknd / Descendants of Destruction) - covers the walkway area beside the lagoon (which then crosses the street to line up in front of Animal Actors and around the KidsZone areas), but guests also can go past this to access the Simpsons Area, including Duff Gardens as well Krusty Burger (the street is usually kept open for exiting guests, so going between these can be a pain). Guests wanting to queue for The Weeknd (or Universal Monsters) will want to stay on the Central Park side, while those in Simpsons can queue up for Descendants (usually around the Kwik E Mart where the S&S area ends). Access point is at the lagoon next to the crepe stand.
(5) Blue Man Group Theater (Hellblock Horror): Although it's not actually a S&S area (since it's accessible from Citywalk and not in the park itself), this is a holding area for Universal hotel guests attending HHN. Access is by the walkway in front of BMG theater (between Hard Rock Cafe and Universal Studio's main entrance, running parallel to the end of Rip Ride Rocket). Access requires both an HHN ticket as well as proof of a hotel stay.
If you have Express and can access S&S areas before park close, I still would recommend doing the NY area and following a similar strategy. Many of those with Express still will try to go through a few houses at the start of HHN without using Express - which allows for second walkthroughs later in the evening using Express when lines are longer. Additionally, if you do use Express, it'll allow you to get through houses faster (including several that have longer Express lines later in the evening) to free up time later for the Scarezones or shows. Additionally, the New York S&S area is one of the larger ones, easiest to navigate and has better amenities than the others if you're just looking for a place to relax until HHN opens.
If you can't access a S&S area inside the park, the next best option is the BMG area for hotel guests. I've seen numerous reports that this entrance is very underrated (and underutilized) with its introduction this year. It essentially functions as a S&S area - but outside the park, so it's ideal if you miss the 5pm entry to get inside the park or don't want to have to pay for a Scream Early ticket. The area releases around 5:15, usually with minimal wait to get inside the house, and sends you into the park immediately to then get in line for Halloween, Spirits of the Coven or pre-queue for Dead Man's Pier or Chupacabra. Although I didn't try this strategy, it appears to be a very good one.
Finally, if you don't have any of those options and begin HHN with the general public when gates open, my recommendation would be to head towards the back of park houses first (Descendants of Destruction, Bugs, and Blumhouse), then hitting The Weeknd/Universal Monsters, and finally work your way towards the front of the park and the 5 houses all on the straight line between the park entrance and the New York Library. Like any theme park, the attractions at the front of the park get swamped first and crowds gradually spill out into the rest of the park. Going against the crowds instead of with them may save some time as the night goes.
I got the new Trick R' Treat harlequin skirt. Wish I would have sprung for one of the purses like your Sleepy Hollow pure or the Trick R' Treat purse--oh well! I'm sort of holding out hope that I'll find a Lil Boo purse in Universal, I'm not sure if those or sold out in the parks or not.
Hello fellow Vixen!!!! Your Trick r' Treat skirt will look fabulous for HHN! If you'll be in Islands of Adventure at all, there's a store over there that would make for a perfect photo spot with your skirt - check out the doors! I didn't see any of the Lil Boo purses when I was in the parks but I also wasn't specifically looking - hope you're able to snag one while you're there!
I guess my question is if it’s worth trying to see if universal will allow a change of night to later this week? Or do I suck it up and go alone, has anyone any experience of this event going solo? So gutted 
