If you look at the Cowboys rivals for seedings in the NFC, it is currently ranked like this, with remaining opponents listed:
1. Eagles 8-1. @KC, Buffalo, 49ers, @ Dallas, @ Seattle, Giants, Cardinals, @Giants
2. Lions 8-2. GB, @ NO, @ Bears, Denver, @ Vikings, @ Cowboys, Vikings.
3. Niners 7-3. @Seattle, @ Eagles, Seattle, @ AZ, Ravens, @ Wash, Rams
4. Saints 5-5. @ Falcons, Lions, Panthers, Giants, @ Rams, @ Bucs, Falcons
5. Cowboys 7-3 Wash, Seattle, Eagles, @ Bills, @ Dolphins, Lions, @ Wash
6. Seahawks 6-4. 49ers, @ Cowboys, @ 49ers, Eagles, @ Tenn, Steelers, @ AZ
7. Vikings 6-5 Bears, @ Raiders, @ Bengals, Lions, Packers, @ Lions
Every other NFC team is below .500.
Now, the Eagles have lost only to an AFC team, while Dallas has lost to 3 NFC teams, so Dallas isn't likely to win any tiebreaker with the Eagles even if they even up the season series and both end up 5-1 in the NFC East.
The Eagles have tough games @KC (tonight), 49ers at home, and @ Dallas. They also host Buffalo. Even if Dallas beats them and they lose 2 other games to finish 13-4, Dallas can only do better by winning out.
But, all is not lost if Dallas doesn't win the NFC East. If Dallas loses the division, they will be the 5 seed and go on the road against the NFC South winner. Any of those teams is beatable.
That would pit Dallas against the #1 seed in round 2 with that long awaited chance of winning and getting to the NFC Championship game.
Well, which team has the best chance of being the #1 seed? I think it is the Detroit Lions. Sure, they almost lost to the lowly Bears yesterday, but they have 1 tough opponent left on their schedule -- @ Dallas. And even if they lose that game and end up 14-3, how will they match up for tiebreakers? Their 2 losses are to Seattle and the Ravens.
Wouldn't you rather go to Detroit in round 2 than to Philly or to SF?
The other thing that would be nice for that scenario is that SF and Philly would be the 2 and 3 seeds in some order, and would play each other in round 2, so Dallas would only get the winner in the NFC Championship game, if they can beat the NFC South winner and then Detroit. Playing indoors should suit Dallas's game much better than going outside @ Philly or @ SF.
That's Dallas's best semi-realistic hope, since winning out is highly unlikely and passing Philly is too.