The manual is pretty good at explaining what needs to be done to a sequence before sending it to Color. It's always been a bit weird because it's never integrated properly into the whole suite completely.
To simplify it a little, basically you need to either breakout or consolidate any nests, collapse any Multiclips and flatten any composites. Also make sure that they are all in a single format type like ProRes422. Also check any file/clip names to make sure they don't have any '/' or '&' etc.
That way it goes back and forth prettymuch without a glitch.
I have tried your suggestion Mr Pi.... can't seem to figure this out. Guess it isn't a real biggy. One of my cameras was a little dark. I tried opening the clip alone in color, that didn't work.
I will do a little more reviewing. These clips were captured direct from cameras.... and are roughly 45 minutes each.