I really think it depends what series of MRAP you're talking about, and whether or not you can drive them out (to the north or through Pakistan). Shipping them home by sea is quite efficient -if- the US Government is able to secure those roads.
If they have to go out by air, it isn't as practical, and the protective technologies will be obsolete as compared to new production if faced by cutting-edge threats.
Mycrofft, although the MRAPs are decent on roads and stable surfaces, they are simply too big and too heavy to perform as well as dedicated scout trucks in most terrain. Even on Fort Bliss, there are plenty of areas MRAPs simply cannot effectively manuver in, and that's on stable, relatively flat sand. For a potential Central or South American counterinsurgency, the MRAP would be a fantastic truck. For conventional warfare against, say, the Chinese Army, the MRAP would be a liability in most front-line settings.