You guys did a fabulous job, especially given the sheer number of unknowns--would you get enough freeplay machines? Would there be enough vendor interest? Would enough people come? For the most part, you hit it out of the ballpark.
My suggestions would be:
1. Have the event be on a Saturday and Sunday, rather than Friday and Saturday. I think more people would come if it were a weekend event.
2. Rather than simply polling Pinside members for the best dates, set up on outside survey (a la surveymonkey) that suggests different dates and send everyone from all sites--pinside, BPA, etc.--to that central survey so you can get a centralized set of responses, and then based your dates on whichever dates get the most vote.
3. To increase the number of freeplay pins, you might want to increase the value of the incentives beyond the free admission and raffles. Maybe every person who brings 2 or more pins gets a free room? Maybe every person who brings 3 or more "not for sale" pins gets either a free room or a couple of hours of free repair time from a local pin tech? Maybe even person who brings one pin gets free admission and an Amazon gift card or something similar? Yes, this increases the out of pocket costs, but maybe a little pay-to-freeplay might help encourage more people to bring pins.
4. Your offers to transport pins from homes to and from the event is a real winner. Maybe starting a network of "guys with vans" who will move these pins for people would encourage more people to donate freeplay pins.
5. Rather than use Pinside, BPA or other forums as scattered discussion areas for PNE spefifics, add more community forum features to the PNE site to creabe the community site where people can post lists of games they will be bringing (or selling), or people can network to arrange transportation, or vendors can post promotional information. This will give the PNE better "repeat visit" value and make it a more effective tool for connecting PNE fans and vendors.
6. You might want to devote one room (or part of one room) to be a "Skill Teaching" area with several different kinds of machines (old EM, 80s, DMD era) where highly skilled players could demonstrate techniques to explain the differences between "regular shooting" and "mode based" games to people gathered around the machine. Part of this could also be "expert clinics" where top players explain advanced techniques in a seminar setting with the playfield projected on a video screen (a la tournament views).
7. MAKE SURE THE BIG LEWBOWSKI IS THERE!