Jeff O sums it up well. Getting there a few days early would also give you time to get accustomed to less O2 availability. The higher elevation does take a toll, regardless of whether you are Ironman or not. It took my ADK brother several days to get used to the elevation last fall. The first couple days were a lot more of a challenge going from 1,000 feet at his home to 9,000 feet and up where the elk were. The 46ers at 4,000 feet are not going to gain you enough conditioning. Sometimes you will have a problem with altitude one trip and not another. But a few days to acclimate will sure help you out.
Just make sure that when you find them early, you don't crowd them and blow them out before opening day.
