How long do you need to see Jerash?
For visiting Jerash, I would recommend budgeting 3-4 hours to spend in Jerash. You may spend a little less or more time there, but that's a good amount to plan for. There are a lot of details to see in the site. And, you want to visit everything in there and not feel rushed, definitely 4 hours.
How do I get to Jerash?
From the North Terminal Bus Station in Amman, visitors can regular buses to Jerash. The buses in Jordan are very affordable and visitors can expect to pay 1JD (1.50USD) for a one way trip from Amman to Jerash. From the bus stop in Jerash, it is only a short walk to the historic Roman ruins of Jerash.