Re: dilema for a doc in the US!
PA is a level above the nurses considering in some states they can even presrcibe the medicine without a doctor's co-signature but in some states they work strictly under a medical doctor's supervision.
It's a 25 months long course and I guess at least 1 year of clinical rotation and then there is on going training as long as they are in the field. It's a very demanding and time consuming job so if your wife doesn't want to carry on with med school because of "time" as a factor then it may not be a good idea.
You can always look into pharmacy, public health, and other positions like Mr. Fraudia mentioned to keep a 9-5 job instead of being on call always.