"Twice as Far' episode description goes:
Two separate groups leave Alexandria for supplies, and while both worry over the future of the community, they will face immediate danger. (via Wikia)
The promo shows us those two separate groups as being Abraham/Eugene and Daryl/Rosita (and maybe Denise in the back of the car?). Obviously they encounter danger in the way and, though Eugene is struggling with a walker, it seems unlikely walkers are all they'll run into.
We also get a glimpse of the cage Morgan was building in episode 6.12 and Rick looks at it quite unconvinced yet. Morgan 'stalks' Carol some more while she's seating on a porch and Rosita and Daryl run - apparently from walkers. The promo ends with Daryl pointing his gun straight to the camera, making us wonder who's he's using it against.
The sneak peek has Daryl and Carol talking about the 'people in the burned forest' and, while Carol still seems conflicted about who she really is (or should be), Daryl clearly has it all figured out when he says he should have killed them, instead of saving them.
AMC has only released two promotional stills so far: