I guess they don't consider this a "party" per se, but an After Hours Event, so ticket holders cannot enter until 7pm.you used to be able to enter a park at 4pm with party tickets.
we have 2 other full days dedicated to MK during the week...2 for HS and 1 for Epcot (nothing for AK since my daughter is too young for Everest and Avatar)That depends. Do you have other days scheduled at MK? Or, will you only have Boo Bash time in MK? If you have other days scheduled there, I'd think time is better used in another park on that day. But, if you only have that day to enjoy MK, tour in the morning/ early afternoon, head back to the hotel, and return for the Boo Bash at ...whatever time you want because you'll have a park pass already. If Boo Bash is your only ticket for MK, then you won't be able to enter the park until 7pm. Lots to consider, but have a great trip!
This isn't a party, it's an AH event.We have always entered special parties as early as 4. Has that changed? Personally I wouldn’t spend the money on a day ticket.

Do you have park hoppers or one day tickets? Sorry, didn't read the OP.
We don't plan to do MK the day we have Boo Bash tickets. We are staying at an EPCOT resort, so will be doing HS in the AM, leave around 3 or 4 pm, wash up, eat dinner, head to MK (leave around 5:30 or 6 pm for bus transportation). Hoping I can hop into the pool for a quick dip...I plan to eventually swim in every WDW pool![]()