One thing I was bit unsure about that solution was that the man could simply have waited on the washroom. If the wife is moderately smart, she will realize the place she left could have only been the place the man got lost, and will return- at maximum man will only need to wait two days; inconvenient, but not enough to screw over entire vacation or try to return to home. Isn't it?
Also, since they chose to rest during their way, you can anticipate the place they were resting was camping ground, RV park, or some random spot near the highway. If so man can simply try to stop one of the cars passing by, explain the situation, and borrow the cellphone to contact the wife. Perhaps the wording was bit too strong in this puzzle? It kinda seemed to suggest they had no choice but to return, which suggested some unrecoverable situation, which above situation definitely is not.
:3