Foreign credit cards are accepted almost anywhere in Israel. It is always recommended to have a limited amount of cash (NIS) in case you have to pay cash only. A partial list of ATMs right on the trail is here. There are many ATMs at a reasonable hiking distance from the trail (1-2 km).

At the airport you can find a bank , ATM and money changing service. There is always a fee for withdrawing/changing money.

I'd suggest that you withdraw at the airport a limited amount of money for the first few days or week, and  continue withdrawing on the way.

 Traveller checks are safer and can be exchanged at any bank. As in any country worldwide, do not carry with you large amounts of cash.