What Pluto probably looks like
NASA is considering a Pluto mission now. Neptune’s moon Triton is likely a good model for Pluto now (Triton is twice its size); in ~2010  Pluto’s atmosphere will freeze out onto its surface as it recedes from the Sun. Triton has ice volcanoes erupting methane.
Triton is a retrograde moon of Neptune (one wonders whether impacts or encounters played a role in that). Triton’s volcanoes are driven by changing solar flux. Note the dark plumes on the surface which mark eruptions (maybe more like geysers).