My recommendation is to go train on Mt. Lemmon once a week. Is there a road up there for running and biking? I'm not sure how much physiological benefit you'd get, but it would give you confidence that you can indeed ride and run at altitude.

I don't think you should be overly concerned about training at 2300 ft and racing at 8000. Are you hoping to place in your AG? Are you planning on a PR? Or is your primary goal just to finish within a reasonable time? If it's the latter, you should be fine.

FYI, I have read a bit of the science of altitude training. My memory is that a difference of 5000 ft, while noticeable, isn't debilitating. I also have had experience living at 4500 ft and climbing mountains to 12,000. Three years ago, I lived, worked, and hiked for 2 weeks in the high Peruvian Andes at the 9000-13,500-ft range. I did experience some high-altitude problems, but I was able to work and hike just fine.

Good luck!

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Do not take counsel of your fears.--Andrew Jackson

From what I understand about altitude training, the benefits come from sleeping at altitude, not from the training. Training at altitude is more difficult, you are working with less O2, so you actually get less benefit from training. If you sleep at altitude, you body will try to adapt to the lower O2 and generate more red blood cells. Ideally, you would sleep at altitude and train at sea level, this is the theory behind the CAT hatch. With only 6 weeks before the race, I don't think you would get too much adaption, especially if you just go up to altitude for your training, and come down immediately.

Check out cptips.com. There is a good section on effects of altitude on phisiology and training. Author is an MD.