Take your Girlfriend and RV (Get someone else to drive if you can) to a shoping mall after hours when the lots are EMPTY and let her drive it around the mall a few times.. Odds are very good she will find it is not all that much difference than driving a car.. Oh it is BIG, I mean BIG, even professional OTR Semi Drivers say RVs are BIG, that's because they are six inches wider than a Semi truck.
But put her in an enviorment where there is nothing to hit, and let her drive it a few laps.. I think she may adjust.
But then I do have a problem in that I give people too much credit for adjust-ability. Or rather adaptability.