I finally found the path of least resistance to getting the kind of helo missions I want to fly (given that I have yet to find any readily available for download):
1. UnPBO the original Chinook mission that came with upgrade 1.3
2. Substitute appropriate SEBNamPak2 units including UH-1D for all original "1985" units
3. Transfer whole thing over to the Vietnam-like IaTrang island map
4. Arrange units in a logical fashion:
a. Start helo with full squad of 8 on board at firebase
b. Carefully place enemy units at first hot LZ to punish slow or high altitude flying yet reward well flown profiles to get through with minimal damage
c. Place casualties needing pickup at another LZ, but reduced to a number that the UH-1D can handle with modified scripts so that victory conditions can be met
5. Edit voice files, briefings, intro, and outro to match new mission arrangements.
I still need to finish quite a bit of #5, but the mission already runs great. Once I have polished it up, I will work on adding ground fighting, a gunship escort, and ultimately support multiplayer.
Starting with someone elses mission sure does steepen the learning curve. I would never have started otherwise.
OFP/Resistance is simply the best