If you ever played Civ 1 or Civ 2 the expansion thing will be natural to you. The further you get from your capital (founding colony) the more dissent (drones) you get. A military unit quells one drone, a military unit with the "police" upgrade quells two drones. Drones don't work, and if they out-number your specialists (empaths, science blokes, etc) you get an uprising. Nothing gets done at that colony then, move a military unit in to quell dissent. There's also some economic-scale-of-distance-negatives in the world economy thingo.
So, have a defensive unit in your colonies (and/or a 1-1 police unit) and keep expanding forever.
You will always be at loggerheads with someone, no matter how peaceful you are in-game. Your original faction and your society ethics will mostly bring you into conflict with someone. Choose the UN (Lal) if you want a chance for peace, or buy them out with the Morganites (Industrialists) or tech-gift them with University (Zarakov?).
It's the beauty of SMAC that you can never sit on your haunches entirely. If you want total peace, you must dominate everyone or win through diplomacy of an economic, technological or military order.
If you've got SMAX, I'll give you a faction file that can let you go a fairly peaceful, yet still moderately balanced route. It's boring though. Peace through superior (faction skill) is the name of the game in SMAC. But you're not limited to what you started with. That's why it's so good.
Edit: yes, mid-red fungus on mid-brown terrain could be annoying. I'll see if I can re-sprite something for you. Is garish purple ok to see on brown? The game is really damn moddable