I play Pathfinder on a weekly basis as GM so I'm a bit of an encyclopedia for that system if you end up going with that.  The amount of customization makes it my favorite system.  That said, JB is right.  5e is a pretty straight forward system.  I don't know how much free content is available with it.  All of the important Pathfinder rule books out are available for free online.

Depending on the time and day this would take place, I'd be interested in joining.  My vote would be Pathfinder, but I'd deal with 5e.