If you've watched the last 3 Niner road games (@ Cardinals, @ Packers, @ Panthers), each game has had a similar quality to it:
The Niners score on their first drive, usually 3 pts, and the defense holds up their side. The score is usually pretty close with a slight advantage to the Niners, then the opponent gets some momentum and scores once or twice to take the lead. Right before half, Kaep is able to get some points, usually 7 going into halftime. After half, Kaep usually has another drive resulting in points. Then the opponent counters and for the majority of the second half it goes back and forth with little scoring, then the Niners have a time-eating drive in the forth with a Dawson FG.
The Niners will definitely focus on the power running game. A lot will be determined by how those runs on 1st and 2nd down go... if the Niners are able to average 3 or 4 yds, they should be able to stay in 3rd and manageable situations. However, the last few times they've faced SEA, including @ SF, the running attack has been stymied, forcing Kaep into difficult passing situations against the #1 pass defense.
Crabtree definitely helps, as it provides some relief for Boldin and Davis. If all three are on the field, at least one of those guys will be single-covered. Another guy to keep your eyes on is Patton, who's been dealing with a broken foot all season but has great instincts. I do worry that he may not be able to physically handle the Seahawks pressure, but he did have 2 very clutch catches against 2 very good defenses in CAR and ARI.
I would put the Packers film to rest... If he's not playing GB, Kaep doesn't run everywhere, in fact he's not used very often, especially against zone defense. He will tuck it down on scrambles, but the Hawks LB corp is fast enough to keep him from getting to the edge. I actually expect Wilson to rush for more yards.
Even if Kaep's running isn't going, he has made very timely, clutch plays in every playoff game he's been in. The Niners as a whole are playing with great confidence, but this game will be decided by who can control the line of scrimmage (as it almost always does).