I think it is "worth it"...but that is a subjective, individual thing. What to expect...
MNSSHP: luv's Not To Be Missed List...
(This is just my personal thing and not official in any way. Caveat emptor - and you didn't pay me, anyway, so you get what you get.)
1. Headless Horseman - he rides before the parades and may be the highlight of the night. (Doesn't ride if the ground is wet and not safe for the horse.)
2. The Boo to You parade, which starts in Frontierland, goes to the hub and on down Main Street, is Disney's best parade, all year long. Try to get a good seat. By "good", I mean on the curb or at the rope. No one place is much better than any other, IMO. But it's more fun if you can see the Headless Horseman and parade stuff easily. Also, at the end, they hand out suckers to KIDS in the front, so a little extra bonus for your time and trouble invested in being up front and defending your spot. The 2012 parades were at 8:15 and 10:30.
3. Fireworks. The fireworks ("Hallowishes") themselves aren't all that amazing, but they're fun and the soundtrack is awesome.
4. The Haunted Mansion. The ride is the same, but there is a ghost who will chat with you as you enter the line and the staff are all decked out. Pretty cool.
5. The barbershop quartet. They're dressed for Halloween and sing Halloweeny songs. One of my favorite parts.
6. The Villains Mix n Mingle. I don't go meet the Villains. If you want to do that, be up front and ready to book over to them when they come down. They don't stay long! But the show is good.
Trick-or-Treating - for kids and adults alike. They give you a small plastic bag when you enter. Wherever they hand out wristbands, they'll be handing out bags. They also sell a larger and more sturdy bag, if you want to get that. If your kid has a favorite pumpkin or something that they like to collect candy in, you can bring it. Lines get shorter later in the night. Sometimes there are candy trails - the one that begins in Fantasyland, back by Dumbo, and ends by Space Mountain is used more often than not...and it only runs one-way, so don't try to start it in Tomorrowland. Won't happen.
Meet & Greets - multiple character meet n greets (e.g. Seven Dwarfs! All together!) are set up around the park. My favorite is the one where you stand in a hitchhiking pose and they add the HM hitchhiking ghosts to it later. You can do M&Gs with characters wearing costumes, too. There are a bunch, but the lines do build, especially for the 7 Dwarfs. A lot of people start lining up for the dwarfs before the party begins.
Dance parties - for little kids (or anyone, really) - they're pretty loud, but the characters do a nice job with the kids. I generally avoid these, but the little kids are very cute, dancing with the characters.
Souvenirs - party-specific stuff to buy, if you want something from the event, like a pin or whatever. People have posted that they run out of T-shirts early in the evening, so if you want one, you might want to get there early. (I personally think they are kind of ugly and wouldn't bother, but to each, his own. ) There is no running out of pins! And no lack of selection on pins, either. If you like to buy pins, you can drop a bundle.
Tickets - MNSSHP is a "hard ticket" event. You will need a MNSSHP ticket to attend. (You do not need separate admission to the park.) The party is a park-wide event and your party ticket gives you access to all of it. I don't buy mine until the day of the party because I won't go in the rain. But if you put off buying a ticket until the day of the party, you risk having them sell out. It's a hard choice to make. Party dates and ticket prices can be found here:
http://www.wdwmagic.com/events/mick...-scary-halloween-party-ticket-now-on-sale.htm
Wristbands - they'll give you one when you enter, if you enter around party time. Multiple places where you can pick one up if you've been in the park during the day - just give them your party ticket. You'll need to show your wristband periodically to the wristband police, who set up human blockades to prevent people who didn't pay for the party from being there. They even interrupted us while we were eating once and demanded to see our wristbands.
Maps - there are special park maps, just for the party. It lists the rides and places to eat that are open during the party, dance party and Trick-or-Treat locations...and has the all-important parade, villain show and fireworks times. They're cure, too. Pick one up! Whenever these maps come out, you will find the info here, so you can check it all out before you go, if you want. Last year's map:
http://www.wdwmagic.com/events/mick...t-so-scary-halloween-party-guide-map-2012.htm
Weather - it can be very hot (especially September or early in October) and it can get cold (especially later in the month).
Costumes - No way to predict temps, so if you have costumes, try to make them adaptable to any temp. Because that's so easy, lol. Adults can dress up, too (but it isn't required. Some do, some don't. Whatever you choose, you won't feel out of place.) Some people go all out on their costumes and some are very funny, so it's entertaining to see them all. Disney frowns upon and may not let you wear masks that will obscure your vision, so leave those out. It is the only time of year that adults can go to the parks in Disney character costumes and many do. I don't know what the rule is on what time you can enter the park with your costume on, but have seen people in costumes as early as four or five o'clock. You can get spooky with the costumes, but not too gory.
Although the party begins at 7:00, they usually allow people with just a party ticket into the MK around 4:00.
If you have an AP that gives you free parking, it doesn't cover MNSSHP. So, be sure to get through the toll plaza before 7:00. If you don't, be prepared to pony up the dough, flyboy! ($15)
If you all are into the horror part of Halloween, check out Halloween Horror Nights at Uni. Tons of fun...but not for children!
Have a great time!!!!