Having watched ( and re-watched) every Viking games in the Peterson era, here is my take and prediction.
Teams can stop Peterson from rushing for 150+ yards and scoring 2+ TD's a game only by run blitzing and/or putting 8 men in the box on 1-2 TE set and 9 men in the box on 3 TE set. If defenses concede 3 yards to AP as the norm on rushing attempts, they will get burned several times a game. The way to stop AP is to run blitz the CB to take away the corners and have the middle stuffed with a safety to keep AP from burting thru the line. SF did this effectively in AP's rookie season and smarter teams have been copying that approach ever since, some with much success.
One way to counter this approach is to just line up with 3 TE's and block everyone, running away from the strong side where the extra defensive player lines up. That is exactly how AP scored on his 64-yard run against the Browns. The Vikes lined up with 3 TE's many. many times that day, and usually lined up with at least 2 TE's for that reason as well.
Another way to counter this defensive approach is to run screens. If executed well, they will pick up big gains. The Vikes run screens well, but rarely with AP in the lineup, which mitigates their effectiveness (although Chester does a good job). A variant on this which was really cool was the fake end around to Percy and then Farve hitting AP on a naked bootleg in the flat, which almost scored a TD against the Browns. A gimmick, however, that will only work if not expected or planned for by the defense.
The BEST way to counter the approach taken by defenses to stop AP is to hit WR's over the middle -- either on a quick slant, or a longer slant/post route over the middle (the kind that TJ hit against the Texans in pre-season), where the safety should be but is not because he is out position to try to stuff Peterson at the line. Hitting the TE over the middle works too -- and we have seen the Vikes do this repeatedly with some success.
The quick slant is difficult to execute well because it requires perfect timing and the QB and WR to be on the exact same page. It is high risk because it has to happen fast -- which means the QB might not see the LB or CB jump the route and end up throwing a pick-6 the other way.
I was eagerly anticipating this season because Farve has historically been so good at hitting the quick slant for big gains -- often long TD's -- when the D was most vulnerable to them. He did this to the Vikes more than once.
If Chili and Bevell let Farve do this with AP in the backfield, I think the Offense becomes unstoppable.
My prediction: if Farve hits at least 2 slants for home runs with AP in the backfield over the next 2 games, the Vikes will be in the NFC Championship game. If he hits a quick slant for a home run with AP in the backfield against either the Ravens or the Steelers, the Vikes will be in the Super Bowl this year (barring major injury on Offense).