Well, since you asked for opinions, here's mine...
A standard transport C-47 in WW2 livery isn't much of an attraction for me. I've seen plenty, they were all very similar, and not terribly interesting.
Now, the same airframe, as a gunship, decked out in Vietnam camouflage, with a cabin full of miniguns and cannon, and the associated sighting systems, is something I'd travel a fair way to see/photograph/fly in. There is one AC-47 on the show circuit, but I haven't crossed it's path yet.
I'd pay to fly in it, especially with guys that flew the real deal in Vietnam, and hopefully do a few pylon turns like they did in wartime. Have headsets for all pax and play recordings of actual spooky missions. You could probably get 8-10 paying pax per flight, with operating expenses less than the four engine bombers. Sell special flights with an A-1E flying along side.
On the airshow circuit, have it do firing turns aimed at show center. I'd love to see that.
Sell inert .50 cal. and 7.62 cartridges at shows to raise funds.