After reading some great posts by folks who took what I had tried (and failed) to do and proved it was possible, I'm giving the worldmap another try.

Since this is for the novel I hope to one day finish, I want as much realism as I can get, so if anyone sees something impossible (or highly improbable) please let me know.

I saw a couple people mention that they really liked seeing all the steps that went into these (like climate modeling etc.), so here are mine so far.

First, I generated a bunch of random fractal planets with PlanetGen until I found one I liked. In particular, this one looked like it was tectonic-friendly, at least more so than most fractal planets.

Used hugin to convert from equirectangular to Mercator so I could see the actual shapes of everything. Then I moved the continents around a bit, thinking about how plates could have been moving, etc., and drew in tectonics around them (Red = divergent, Green = transform, Purple = convergent, Blue = subduction, Pink = hotspot).

Next I used the tectonics to draw in the basic locations of island chains (in black).