I do have to ask a few questions.
How many people here have actually organized a conference of any size? (JW convention experience counts only if you were one of the people that negotiated the contracts with the buildings and hotels, planned the program and scheduled the speakers)
For several years, I worked organizing 2-day conferences from 100 to 300 people in the field of educaiton.
It took several committed, reliable people/committees starting the year before to arrange for them.
1) a location of sufficient size
The good places go fast; book ahead
2) food arrangements
Food provided so people don't have to leave the meeting area
3) speakers
Travel expenses, hotel, usually are paid for by the organization inviting them; yes, and there may even be a speakers fee for a big name
4) people to put on the break-out sessions (and people to do the introductions/see that the proper AV equipment is in each room, etc)
Could be in-house ex-JWs; but if you bring in non-JW people, don't assume they do it for free.
5) registration, name tags (if used), printing hand-out schedules
6) Rooms blocked at a nearby hotel/or in the one the conference takes place in
How many; how much; which depends on how many people are coming
7) A clear view of the theme and goals of the conference so you know who to invite as speakers and to handle any break-out sessions.
I'm not saying it can't be done, just that it is more than organizing a party. If you want speakers to commit, you need a clear plan so they can know if they have time in their schedule.
And then no matter how well you prepare, the power can go off.
Blondie