Depends on the situation and how far you want to go with it. I'm in a similar situation myself. I don't really want to go out and trick-or-treat this year (I really don't need all that candy), but I still kind of want to use Halloween as an excuse. My problem is that I want to do the freaking works. Get my eyebrows plucked, ears pierced, nails painted, arms and legs shaved, etc. On one hand I think it's the perfect excuse to get my body more femmed out. If someone is daring enough to ask why, I simply reply with, "It's for my Halloween costume!" On the other I'm a bit scared how others will react.
I say if you're willing to deal with any ->-bleeped-<- that comes your way, you should totally go for it. Trust me when I say that the straightest of straight guys dressed up as girls for Halloween plenty of times at my school and hardly got any ->-bleeped-<- for it. Some of them even looked really good! Others...Well, I'm not entirely sure why they would want to dress as a girl if they weren't going to put any real effort into it.