dgfred - Have played the Ironqois before and they are definately in the "2nd choice" group (along with Inca, Ottoman and a few others, Celts are alone in the 1st choice). I find the trick to getting iron working is meet evryone you can on the continent and someone will be dumb enouigh to trade it!!!! It costs alot but all military based techs do. Besides I usually have a tech or two to trade (especially if you know a civ that they do not).
The main kick in the proverbials IMHO is the iron itself. In my current game I had to build a chain of 3 cities through not fully claimed enemy territory or a city on an island that was all tundra, hills, and mountains to get the stuff. I decided to do both as iron has a habit of "jumping". That slowed developement badly!!! (Nearly as bad as ALL the coal being on the opposite continent and the Americans having the only surplus, until my naval amada of 14 fully loaded transports with 2 bomber laden carriers and support escorts arrives!)