Depends what you mean by "challenging." Anyone can do it, so in some sense it's not challenging at all. But how long you will have to wait depends on how early you arrive and how busy the park is that day.
I could be wrong but I would guess that on a moderate crowd level day, if you arrive at the gates 45 minutes before the resort early entry starts, then your wait should be 30 minutes or less.
If instead you show up at the gates right when resort early entry starts, and it's a very busy day, you might have to wait an hour or more (but still will probably be waiting a lot less than if you try to ride at any other time).