The map layout is basically the same every time, and you don't have to kill every civ. I gifted a few capitals to one of the forest civs, and made sure the other one never built GW. (By repeatedly dowing him and accepting cities in peace deals, leaving him with only one city, slowing his tech and not giving him time to focus on that. He never built much) Also, I started in the mountains and ignored the other mountain civ, gifting him cities. Problem solved. I did have to deal with GW in my first game if I recall. The secret is to get #1 in military fast and then DoW everyone. Even the civs you're nowhere near will give you cities in peace deals, so that by the time you have to deal with them, they have only one, and their tech rate will be terrible.