I just finished building one of these--it was the Lindberg Snap-tite re-issue; just waiting on paint now. To put it lightly, kit was VERY, VERY basic. There is no hoist, no rotor head details, you'll have to add rotor droop if you want it, no FOD deflector for the turbine intakes, no pitot tubes, no cockpit detail except for a couple of plastic lumps in the seats that are called "pilots," and two flimsy pieces of flash that might be taken for cyclics. The external fuel tank mounts are huge and very simple. The clear parts were thick and like looking through a kaleidescope.
So rather than trying to scratchbuild anything inside or make new clear parts, I painted the inside of all clear parts black. I ended up buying a resin conversion kit to make it a USCG HH-3F Pelican (from Hawkeye Models Australia, kit #CS-18).
Long story short, it was a rough kit, but I wanted a Pelican to add to my collection, so I didn't mind the extra work. All the shortcomings aside, and the fact that I haven't found a better kit out there, I'm pretty happy with the end result, and will be more so, once I get it painted and marked! Keep us posted on yours!
By the way, Squadron Signal's H-3 in Action is a very good reference source!