Not sure if I understand question correctly, but idealy the cable should have source and destination termination both matching cable's impedance, usually 75 ohms for video lines.
Generally, if you have mismatched destination termination (you said your CRT is 1-5K), but you have proper source termination it will still be ok, reflections will be absorbed by source almost 100% and will not be seen by destination (just one reflection happens). Except that voltage levels at destination will be double. If you have both ends terminated, then reflections does not happen at all (idealy), so this is preferred. Also voltage levels will be what they should be (because usually the driver is made for destination termination to be present). If you have both ends badly terminated, then all kinds of funny business can happen with your signal.
So source should be 75, cable 75 and you probably need 75 on the CRT inputs (load termination).