So here's the thing, you don't need to have the hotels and things figured out to declare the Meetup.! You certainly don't need guides etc and itineraries. This is not a business or club trip you're setting up where you have to have a total package figured out before presenting it.
Putting together attractive options will help attract more people but that can be done as you go along.
It's Place and Date that is important at this point. Look at the western gathering, there's not even a date yet but they have declared the place. You could go that route but I thought it was pretty fixed already.
I think you're right about the 9th, if most travel /hotel is Saturday.
So step 1 is declaring where it is. That is , you tell trek and she starts a thread/ group.
Step 2 is the date. Ideally it's done with step 1.
After those, we can take it from there. Possibly have a few people strategize about what we need to find out and create.
One of the things that's different from setting up a prearranged trip is that people will contribute info. Look at the off piste thread. Already you've got people posting options.
I guess the upshot is the gathermeisters don't need to do everything! Others will contribute if you ask.