over 100?? what turn on you on? how much crashing are experiencing at that level? Difficulty? I just dumped a 49 city 512 turn game because mathematically it was only a matter of time for me to win and the game would crash every 10-15 turns or so. You don't manage all those cities hands on do you? I have found that around 40 cities with all the requisite resources you are sitting well enough to use a good percentage of cities for continuity/teleport hub as you mentioned. 100? wow. how many hours to achieve that? Oh yeah, your avatar....Squad Leader?
he he he, I've been playing the current game over a week off & on, I'm in no big rush. It's roughly turn 440, there are two AI left in the game & I'm researching spell of making, so it's almost over now. I have a 64 bit system with 8gb ram, so I don't crash as much. I probably average a crash every 15 to 20 turns on continuous play if I don't save & exit first. Most of those cities are just caravan hubs for road network purposes & caravan booty or resource holders/border expansion nodes. I only build up a small number of them, some of the big ones were captured in battle. The ones closest to the enemy are typically squad manufacturing hubs. The rest I don't manage at all except when caravans die & I need to replace them. I also have auto save set to every turn, so the worse cast is that I'll have to backtrack only one turn at most if it crashes. If you actually want to see the game for the hell of it, I have the saved game file posted in the "saved game thread" (I'm not sure what the title of the thread is exactly right offhand).
Right ! (ASL, advanced squad leader), I was a playtester & I'm highly conditioned to extreme detail, cost-gain anaylysis (whatever that term is), and micromanagement given my ASL experience. 
There is an online version of ASL called VASL if you're familiar with the game & maybe interested:
http://www.vasl.org/
