Thank you for you interest and help. In the interim I have more or less been able to trim the old DVD to eliminate a blunder or two and cut it down to 2 hrs. Not that it was easy or very efficient. First I converted it to mp4 and then used QuickTime to trim it. Then I downloaded a free -- no doubt temporary -- editing program called VideoPad. It comes without useful tutorials or instructions. I tried to blunder through it with lousy, LOUSY, results. Tried several times. There is tech support ONLY if you buy the damn thing, although they claim you can get a fast refund if you don't like it. SURE!.
Anyway, I tried iMovie again, this time with the trimmed clips I made with QuickTime and it sort of worked okay. There is still one glaring trim where iMovie preview shows the flow perfectly but the finished product includes some lip-flapping (no sound) of a brief cut I had made. I will have to live with it.
Again, thanks for your interest. I will check out the tutorial in case I ever have to do this sort of thing again.
