Hi,
I own a Road King 1st version.
I got very close to channel 3 vintage w/EL34 and "tube rectifiing/bold", with the SOLO 100 LEAD in AxeFXII.
The best results I got going for channel 4 modern w/6L6 and "diode/bold" are with FRYETTE D60M (also FAS modern) + a tone match. The tone match is very easy to do with this amp because it has a "slave" output that reproduces exactly the signal (at line level!) sent from the power amp to the loudspeakers. It's a perfect way to tone match.
The tone I get is very interesting : more clarity and still that same (or even better) feel of "richness" in the sound, without the background noise... and the ability of playing at low volume.
The only difference for me is not being able to reproduce the sound of hi gain on the amp + guitar volume knob turned down, loads of bite on a clean/edgy sound. Haven't found the way to do that in the AxeFX yet...
Anyhow, I'm selling my Road King.
+ Tom