When you say "runs all over DFW for work" will she be predominantly doing city or highway driving? Hybrids shine in surface street driving where they can utilize regenrative braking to recoup energy lost to heat. Diesels shine in steady state highway driving due to better thermal efficiency in the engine.
Long answer short: If she does a lot of surface street driving, buy a hybrid. If she does more than 50% highway driving, I'd opt for a diesel.