travel from Jerusalem to Amman

This is probably not the right forum for this question. I believe crossing over the Allenby bridge is tedious and time consuming. Also, I believe if using this border, you must have a Jordanian visa ahead of time - it is not available at this border.

You should check out the thorn tree on the lonely planet website where you will find all the details about the various crossings between Israel and Jordan. I myself am planning on using the Southern crossing between Aqaba and Eilat in June.