PT has drop in LED modules for some of their 2AA and 4AA lights (both head and hand carry). I have a PT Solo (2AA) and got the LED module for it. Battery life ratings are 40 hours for alkaline, and 100+ hours for Lithium AA. This is the same as the PT Matrix: same module.
In the light environment that you describe, this would be adequate. The module is perfectly engineered.
There are other and brighter LED headlamps. The Septor (Streamlight) is said to be quite bright. If they made it in 3AA it would be even better.
Another and very bright option, is to get a modified AA Mini-Mag with a Luxeon Star LED, and put 2 Lithium AA batteries in it. Also get a Nite-Ize headband and a holster for the belt.
One Luxeon Star (LS) is 10 - 15 times brighter than an S rank Nichia White LED. I have a Lightwave 4000, which has 10 White LEDs in it and uses 3D batteries. My Arc LS with 2 Alkaline AA is
brighter, and since it happens to have the high dome optics, it is also
better focused!
Believe me, it is worth the price to go with one of these. Even the modded mini-mags with the LS in it, is a very nice, and readily available aternative. CMG also makes an affordable LS flashlight. These things work longer than incandescents, cause they have a much lower threshold voltage (minimum to get the bulb to light).