6" is the most for embark or disembark.
It's a pain, as the model is around that size anyway, and jumping out of terrain won't get you that close.
But, being open-topped, you can dive off the front, and don't have to exit via the 'doors'.
You can't assault on the turn if comes in (
IIRC), but you can:
Move 6", disembark 6" from the front, fire the launcher and guns, and assault the usual distance.
Hopefully, you'll blind them, take out a few models with the
LSS's gun, and a few more with assault weapons. If you take shotguns, you might even wipe out the enemy without assaulting at all (yeah, right

)