I have some cakes I plan on making Friday for some parties over the weekend, and want to help myself by making somethings ahead of time.

How long will BC be good for if I at least make that ahead of time?

I'm going to guess you are talking about a powder sugar and crisco/butter type of recipe. It it good out on the counter for a week or two. Good in the fridge for about a month. It can also be frozen.

I ALWAYS do things days in advance so I'm not stuck craming everything into one night (I work full time in an office too). So for example, on the weekend before, I bake the cake and freeze it. Monday or Tuesday I make my buttercream and/or ganache and put it in the fridge. That way when Thursday or Friday rolls around I just take it all out of the fridge to come to room temp and then Im ready to go when I get home!

It's totally ok to make your buttercream a few days in advance.

Sweet! Thanks guys