I did an SIC program hauling checks part 135. No jet time mind, but after that, I stayed on as PIC. I think it's a good way to build time and I think the flying you do is fairly respectable and definitely a rung on the flying ladder. I don't think prospective employers would turn their noses up at it - at least I HOPE not.
Don't know how closely this resembles what you're talking about but it sounds like there are some similarities. The comment about the Green Card is probably fair though.
Perhaps you could give us some more details.