Everyone who travels to the past can drink nothing but buttermilk for weeks. Girl strips down to bikini. We Are Not Alone.
If the aliens turn out to be evildoers who will provoke the heroes into riding dinosaurs mounted with laser rifles in order to fight them, WIN. If the aliens turn out to be underground-traveling pseudo-hippies who teach the bad humans about being kind to the environment, FAIL.
Bring back the cute little girl feeding the dinosaurs.