That helps. I think I see why my post is confusing. I think I was incorrect in thinking that by having three AA batteries in total as opposed to just two AA batteries I would gain more mAH (1700mAH being the assumption assuming a single AA battery is 1700mAH). After reading some more that does not seem like that is the case? Adding an additional AA battery will net a higher voltage but not provide me the additional capacity of another battery, correct? I don't need the extra voltage from the third battery for my project, as it only requires 3.3v to power all devices.
Your last paragraph is what I was originally asking. I understand the regulator will add its own additional losses but under my original flawed thinking, any regulator inefficiencies would perhaps be outweighed significantly by the capacity from an additional AA battery (does not seem things work that way).
I was planning on just powering all three components from the regulator and using a sleep library to put the micro controller and radio to sleep while not in use. Given all this, it appears the regulator may not actually net any additional battery life. I suppose an advantage to using it would be a more consistent voltage.
I understand how to measure current draw of a component such as a sensor with a multi meter but how do I measure the additional current draw of the regulator itself, both under load and quiescent current, so I can see what the additional losses of using it will be? If I can measure that, I can try a few different types out and see what works best.
Thanks for the help and sorry for the confusion.