Lots of good info already posted.
I would heed the advice given by others by, if possible, avoiding the Moab/Arches area during the dates of the Jeep Safari.
Jeep Safari 2017 April 8-16, 2017Also, be very prepared for snow during that time on your trip especially when travelling to and from the area. It is well known that spring brings the heaviest snow fall events in the Rockies so be mindful of the weather for approaching storms with contingencies for re-route if necessary.
One other thing is I would disagree with the statement of Jeeping/ATV/SxS prime time in UT being summer. Spring and Fall is the prime time as it is not hot as it is in the summer.