have it cut wrapped and frozen, ship it next day air freight. Marked and shipped as frozen meat. I once sent an entire bison, cut wrapped and frozen to my local Pa airport from Utha. It cost me $254.00. and was frozen rock hard when I picked it up the day after I got home!
As for antlers, unless it is of book size ( if that matters to you) they can be done the same way. OR take a Sharpie pen and draw 3 lines across the skull plate on a 45 angle, next saw thru the lines..this will asure your taxidermist will get then aligned properly. take old garden hose and duct tape it VERY well to all points, nest the antlers together as tight as possible, then duct tape them together as well. Put the whole thing in big trash bag then into a HEAVY CANVAS duffel bag
BUT first you got to shoot a bull/buck good luck! MH