@phinds noted in a recent thread that energy is not conserved on a cosmological scale, which hadn't occurred to me before, so I did some reading and happily the concepts were easy to digest and things I already understood but just hadn't connected the dots myself on regarding the implications for energy conservation. I think a photon sees itself losing energy, the red shift is real as opposed to apparent. Is this correct? Maybe a better phrasing is to ask if a freely moving observer traveling along with a photon sees the wavelength of the photon increasing over time. I think the answer is yes. Is that correct, at least according to GR? There can also be an apparent red shift between successive photons caused by the source moving relative to the observer, I am not asking about that and at least I hope I am correct in thinking this is completely different than a red shift of an individual photon caused directly by expansion.