Me either, I'm a Paint dot net guy, but its been lacking some features of late so Krita (which I hate) and Photoshop it is.
I've been messing with NitroGen a lot, the config file especially, and the height-maps and turbulence file, plus I've altered the shape of the snow, forest, desert and crater splats but I too am at a loss for a few things.
Namely the mask file (what purpose does it serve, 'cause I've been generating fairly decent worlds without altering the mask).
And roads in city hubs are a freaking mess all the time, a patchwork of asphalt, broken asphalt with gravel and pathways littered throughout. There's no rhyme or reason to it. It's like the city planners said "Just throw down some roads, the buildings come later". Technically he was right, but jeez-Louise. Roads to and from Poi's and hubs are fine, it's just inside the larger clusters of buildings that the roads go haywire.
I have tried to manually edit the roads (splat3.png) file, it was long and tedious and in the end I must have done something wrong, what I don't know, but I got a tonne of console warnings (yellow) about color info being wrong on the file dtm.raw. I surmised (with Photoshop) that the merging of channels (RGBA) didn't go so well but am stumped as to what actually went wrong. Plus I'm a total noob to Photoshop, who calls "Flip Horizontal" mirror? Flipping is flipping, mirroring is totally different, oh well, whatever Adobe, thanks for the learning curve.
I am loving the program though, it's a god-send for those of us with krapper-potato PC's. I'll be paying lots of attention to any posts in this section and will collaborate my findings and conclusions if I think they are pertinent or haven't been covered already.
My next goal is to grab satellite imagery of my area (Niagara Falls baby) and work with that height-map. Should be cool to see the falls, even if they don't have water spilling over the precipice.