I've done that race a couple times. Your gearing should reflect your riding style. I like to spin up hills, so I threw mountain middle ring on the front and I think a 28 on the back and took everything else off to shave weight. I would say you want to get as close to 1:1 as you can. Washington is steep and relentless there are literally no flats, so don't expect to recover. The steepest part is the last 100 meters which i think is 22, the rest if I recall correctly is avg 12 with several 18 stretches. If you come off the bike you may have a hard time getting going again.
Check out this site and the tin mountain site. The people on the tin mountain site can give you better info on gearing, and there are a couple of shops in N Conway that may mod your bike for the race.
I don't think 'being in shape' is really a factor. You are not going to make it if you are not in shape, and you definitely won't make it if you are not in shape and you try it with your standard road gearing.
I love that race, just not a huge fan of the 400+ entry fee.
Weather can be a huge issue so make sure you pack a lot of layers and bring stuff you can get on and off w/o stopping, b/c as i said you are likely to have to go downhill to get going again.
Last thought, if you have the time Mt Ascutney in VT is about half the length of Washington but similar pitch and you can ride it anytime. Take your time double it and add ten minutes and that is likely to be pretty close to your Washington time.
Come back here and post your experience after the race. One of these days I'll pony up and do it again.