This may seem silly, but whats the best way to sharpen a dowel rod so that it will go through the cake boards?

A 'dedicated' pencil sharpener...one used JUST for the dowel sticks. They make one for the kid's pencils....adjustable to the larger pencils. That would be the one to find for different size dowels.

That's what I use too.

I bought a cheap electric sharpener... And it works great!

same here, pencil sharpner with 2 different size openings that I keep with my cake decorating supplies so it doesn't accidentily get used for pencils

I love my electric pencil sharpener. You can find them pretty cheap and they are very quick compared to the little manual ones. You will want to use it just for cakes though so there's no chance of getting pencil lead on the dowels.

pencil sharpener as well

Dedicated electric pencil sharpener in the kitchen and a dedicated plain one in my cake emergency travel kit.

If I cant find my pencil sharpener, a serrated knife will do.