Guided tour Israel tour to Jerusalem/ Bethlehem and Dead Sea/Masada; what currency?

We are doing 2 day tours with Guided tours Israel out of Ashdod, one day to Jerusalem/Bethlehem and the next day to the dead sea/Masada. I know that the company wants US or Euro's to pay for the tour itself, but what currency should I bring for the entrance fees to Dead Sea and Masada, shopping in Bethlehem and for lunch?

Should I get Shekels for the trip or have people found that they preferred or easily accepted a different currency? I like to use local currency where possible but if I don't actually need to get any then its one less currency to have to lug around :)

I have been in close contact with Leo from GTI as I am organizing the tours for our group from the MOS 10/20 sailing. He said that we can pay the entrance fees in US dollars but should bring some local currency for souvenirs, snacks etc.

For Bethlehem we just charged purchases in the stores on our credit cards.

Keith