Two obvious solutions, from a non Morgan owner.
1/ travel light. I can recommend the wash and dry overnight grundies. One of those airline freebie toothbrushes, and take only one credit card.
2/ Arrange for the wife/ partner / crumpet to travel to the destination by train / bus, and use the passenger space for luggage.
To be a bit more sensible, the key is to travel very light as with any small sports car. External luggage is only viable if you are going straight to the destination - theft is the risk. Pack everything possible inside the car which means lots of small packages.
