Hi Roscoe
I was an external loads (Hoist and Cargo Hook) check airman for one of the large operators. In general the cargo hook assembly is functional but watch out for the following:
1. Where the checklist directs you to test the cargo release pushbuttons (P1,P2 and cabin if fitted), this does NOT include the cargo release emergency pushbutton on the centre console. Very loud and embarrassing mistake that you only do once.
2. The cargo hook load indicator is a bit like the 'Pirates Code' in that its 'more what you'd call guidelines than actual rules'. Probably accurate +/-15 %.
3. 90 Kts Vmax for all loads is painfully slow to a 139 operator and requires some old fashioned fuel planning in strong winds.
The cameras are excellent, particularly if you have the centre screen fitted. Do check they are installed correctly by placing a piece of paper with forward, back, left, right arrows into the field of view as I have seen several incorrectly installed ones. They offer great views of the hook and the load and allow very accurate load positioning.
I have never flown a load sortie single pilot but I have put loads onto elevated platforms and scooped water on instructional sorties (which are effectively single pilot).