Caffenol certainly works as a print developer. I used it a while back when trying out Parodinal. The Parodinal works fine, by the way, and also works as a print developer. As I recall, I used 1+10 dilution for Parodinal for prints. I used the regular mix for Caffenol - just Arm and Hammer and coffee crystals (Maxwell House Rich Dark Roast - that's what was available). It may have taken somewhat longer than Dektol or the Agfa Multicontrast (I was using the latter during the same printing session), but I don't recall it being excessively long. At any rate, I was mucking about and doing a number of other tests at the same time, so it may have been longer than I remember. I was using Kodak Polycontrast III RC which was at least 15 years old and Agfa Multicontrast RC (quite recent). Also, some of the prints were from old colour negatives with an orange colour cast, which made for long exposures and development more or less to completion. I never got around to using the Caffenol for film.
For the RC paper I used, the Caffenol stained/toned it a brownish/sepiaish colour not unpleasant, and possibly quite nice for the right print.
Since I have 7 litres of Rodinal set down, I havent bothered with more Parodinal, but as far as I could see it was pretty much equivalent.
Give the Caffenol a try what have you got to loose a few sheets of paper? I cant comment on fibre based papers, and perhaps you will want to give it a bit more zip, as Donald suggests.
Cheers,
Clarence