I haven't tried it, but the general idea of setting up a dual-boot computer is well understood and pretty reliable. As long as you have a way to go back to the way things were, with old Windows, it's safe to experiment with something new.

The Chrome OS seems like a smart choice for getting more mileage out of an old computer. Practically from the day Bill Gates founded Microsoft, people have observed that each new version of Windows is more bloated than the last, and every new version renders an older generation of hardware obsolete. Doesn't have to be that way, because obsolescence is a matter of context--that old laptop isn't obsolete as a Chromebook.

I'd say give it a shot, and let us know what happens.