@FirstVisit1972, we will be there on 9.16 too!!! It’s our first MNSSHP. Our kids don’t know yet. That’s the one thing I’m keeping a secret til we get there.
Enjoy! The parade and fireworks are awesome!
9/16 is our dates too! 
You will be fine. Short waits for the rides. Try the trick or treat “trail” between the walkway behind Space Mountain. This one is missed by most. Also on the lower boarded walkway area that goes along the river that the riverboat travels is another trail with candy that is not as crowded. Have fun!
There are lots of reports of all rides being “walk-on”. In the absence of any data, does anyone have a clue as to what the lines for 7DMTrain might be? TP seems to think it’ll be over 60 minutes almost all night, but that seems to be based on mere crowd levels & recent data, not on any MNSSHP data. If everything else is “walk-on” (and wait times after 8pm seem to indicate this), is it really likely that 7DMT will still be >60 minutes right on up until midnight?
Anyone wish to take a stab at this? 
Totally subjective guess here – but the party crowds really empty out after the fireworks, so 10-12 is a lot less crowded in general…
Interesting. Suppose we used an analogue? Space Mountain has similar waits to 7D today for example: hour-ish all day. Would it be fair to see what SM does during a party? SM was a walk-on for me during the party.
Thanks for all the tips and advice!