They don't need to be super smooth. In fact, a little rustic is fine. However, I want them to be light colored and to show the grain. Right now they are simply dull gray and fuzzy. I tried sanding, but the gray goes pretty deep and sanding didn't remove the saw marks (and the gray in the dips between the saw marks). A band mill creates lots of logistical and $$ problems for me. It seems like a hand power planer is the way to go. A buddy has one he insists on loaning to me with a "jig" for sharpening the blades.
Once I plane the beams, I will cover them with cotton/poly tarps until we start building in August. I'm assuming the tarps will keep them from re-graying. Although, I better make sure there is good ventilation. Thanks!