In recent games we came across two scenarios of things with Force Push that aren't covered in the rules.
The first being the push someone off of a building, there was a squad of rebel troopers with an objective who clambored up a building and while Vader couldn't get into melee with them from his position, he was dead on for tossing them back off of it.
For the time being we went with the effect being the same as another clambor move and the same roll for survival, but there isn't anything I can find that says what happened.
The second thing was Luke managing to get into a position to push Vader off the map rather than an actual fight there (Vader eliminated someone running with an objective there and then got hit for it). Rules seem to imply that it would be the same as if they wandered off any other way, but I just wanted to know about it.