It IS expensive!! Let me tell you our plan, which I have modified my attitude about after reading several posts from fellow Disers...
Are you familiar with the Haunted Carriage Ride at Fort Wilderness? It gets rave reviews!! Last year, the price was $60 per family/ per carriage and the event entails a 30ish minute ride through the Fort grounds, while the driver narrates Ichabod Crane's tale in a living rendition (expect a fabulous sighting of a main character). This is a very cool and reasonable alternative to MNSSHP!
My thoughts...
Dress up and head to MK. Enjoy the park until closing time. It you want to extend tour time in MK,make an ADR at a TS restaurant right prior to 7pm. Sometimes they will escort you to the exit after dining, sometimes not. You cannot stay and take advantage of all the Party offers, but you can enjoy the decor and atmosphere as you leave. You may or may not, see the early Parade as you exit. Some folks do, others don't. So appreciate it as a bonus if it happens, but don't expect it to happen.
You can then take the boat from MK to FW, do the carriage ride, enjoy the EWP and Hallowishes from the Fort's beach and call it a night. I wouldconsider bringing some Halloween candy to enjoy during the ride and beachy stuff.
Much cheaper,some of the MNSSHP atmosphere (including lots of folks in costume), candy, the HH during the carriage ride and the EWP and Hallowishes! Fun!!!
Hope that helps.