If you have an orchestra then the money you make from the event needs to be distributed to the orchestra.
Oh right, I was assuming you meant raw ticket sales.
I don't know if I could trust one person managing the orchestra for me, I guess I am a control freak in that respect.
Albany isn't a big place.. Quite a few members of that orchestra I knew as school teachers who conducted the concert bands or ensembles I played in during highschool.. and then they became my musician colleagues when I was playing in the orchestra pit for theater shows, and as I got older they then became teaching colleagues who threw me my first ever piano students.. ...Beyond that, my parents were also school teachers, so some of them were even just family friends... I guess I have a level of trust established..
If this is the case what are you waiting for! I hope you are not doing a free concert because you should be paid plentifully for doing this type of concerto.
Gees, there's no way it'd be free..

it'll cost me an arm and a leg to do it in the first place.
The hardest part is selling the seats, if you can do that then get crackin! I know playing in the more "outback" towns can draw the entire population to you, Albany must not get that many performers and it is quite a rich town (in terms of average rent paid there) so yes I am sure people would jump at the opportunity to hear some live piano music (and rach 3 for that matter!).
The old town hall seats about 300, I think this would be an absolute piece of cake to fill.. possibly twice over... not that thats a big concert or anything, but it would be as many as the venue could handle so whatever. There's a new hall now though since I've been there.. so I dont know what kind of capacity I'd be looking at.
The "local" vibe would be a major factor.. with orchestra you'd be looking at minimum 20 people with friends/family to drag in.. all local music students would be advised to go (beats going to perth to see that kind of thing) etc. etc.
Albany has a STRONG annual eisteddfod full of predominantly classical performances, and it sees an audience beyond just parents/family of music students so I suspect there would be plenty of just general classical music fans that would come.
To my knowledge, this kind of event has never gone unsold in Albany as a once off.. possibly a very different market, but to illustrate - I was the pianist for a local theater groups performance of "Oliver" one year.. we sold out 10 straight shows.
I could be wrong ofcourse, but thats the impression I have from growing up there.. I'm sure its a very different deal to do this kind of thing in a state capital though... all my optimism stems purely from the home town factor, and people I personally know.
But wouldn't rach 3 be a little upperclass for most listeners? Would you want to play a collection of piano solos also?
I'm not sure to be honest though I doubt it would be too upperclass.. I would anticipate doing a "selection of solos/intermission/concerto" type thing. Unless the orchestra wanted to make more of it and we ended up with "symphony/intermission/concerto" or something.
I'm always up for concerting . I'd certainly be happy to play 2nd piano, we could do some other duets together also
Let me know how serious your project is and we can get the ball rollin 
I'd love to say 'lets do it' - but I just can't guarentee that i'll be ready by any rough date.. my practice at the moment is just too inconsistent to be able to be sure of anything much.. I'm not a full time pianist at the moment (I spend a reasonable amount of time in my fiance's business) and we are getting married in May. I'll know better where I stand after that..
I would definitely want to do it in the future though... am open to discussions on repertoire.