There is a hike near the tachana hamerkazit that takes you to some ancient ruins. another idea is gan sacher, with the extended botanical gardens that are adjacent to the old monastery there. both are nice, near central jerusalem, and are free.
– your other options include the tunnel tours, a walking tour of the old city, any number of hikes up north or down south(depending on how outdoorsy you guys are), or you can check out some of the beaches.
***caesaria is particularly beautiful, with local tours of the ancient ruins and fruit orchards. the beach is usually empty so tznius should not be an issue