I think the best game tomorrow will be Park River vs. Linton. I don't expect the others to be as competitive, though Stanley may give Central Cass some headaches. I'm not too familiar with Linton, but watch for Sydney Larson in the Park River game. She makes that offense go for Park River and is solid on defense (20 kills and 27 digs against Hillsboro in the Region 2 championship). Kirsten Johnson has also been hitting the ball extremely well as a sophomore for Park River.
If Park River keeps their great defensive play from the Region 2 tourney, I think they'll get into the semifinals handily.
Kenmare vs. Langdon in the semifinals would be a great match. I think the winner of that game would be the favorite to win it all. You have to keep your eyes on Katie King (Kenmare) and McKenzie Hart (Langdon). Langdon has a couple other girls who can hit the ball decently as well, but - from what I've seen - Hart hits the ball harder than anyone I've seen in Class B.
Look for Central Cass's size to make an impact should they make it to the semifinals. I think Park River's back-row defense plays a bit better on average than Central Cass's, but I think Central Cass moves the ball a little better and has some more size (four players 6' or taller on the roster, though I think only 2 or 3 play) up front. Offensively, I think it's a push, with Courtney Dixon anchoring the attack for the Squirrels.
Both semifinals should be great games.