It sounds like a lot of what you want can be done with some recoloring/combining of the RTP set. It's pretty easy to do, and I encourage you to learn how to do it yourself. I say this because you know best how you want your game to look. I spent all of last night putting together new tilesets for my own project, and time just flew by ^_^
As for "desert town desert season," I'm not sure what you mean exactly by that. I guess it's like The Dry and The Rains on Giza Plains (that rhymes!) in FF12?
And as for the desert-sounding music, it's pretty subjective depending on what mood you want - desolate vs. thriving community vs. secret village of desert mercenaries... you get my point. The desert city in my game is an isolationist kingdom. Go to
vgmusic.com and select a video game console from the 'Music Menu' - it's got MIDI files from all the old-school games you've played, and everything else you didn't.
Finally, here are some cacti with needles, one with a flower: