You can try several surfacing methods and finishes to bring out the colors of the beetle kill pine. Surface planing to a very smooth finish is good, but for a more rustic uneven appearance, try light belt sanding with the grain with even as coarse 36 grit. Just to take the fuzz off. You can leave the circle sawmill marks showing to create a old time look.
Then try an oil base finish to bring out the blue and tan colors. Several coats of polyurethane with light sanding between costs will create a very smooth finish over the saw marks.