Croatia and Montenegro
 

Just booked flight from SFO to Dubrovnik and back to SFO - flying in August 30 at 9:30a and leaving on Sept 11 at 11:30a. We are two adult women who love to travel. My friend's family is from Montenegro so would like to include in our travels. We have 11 1/2 to 12 days and are hoping for some suggestions on the itinerary. Neither of us have traveled this part of the world. We are looking mainly for the most efficient route to see as much as possible as well as recommendations on how to get from place to place. Thanks.

Do you know where in Montenegro your friend's family originates?
Several years back, I did an itinerary that included Kotor, Korcula, Lastovo, and Dubrovnik. It involved some backtracking through Dubrovnik and limited time there, which I had been to before.
Do you prefer sticking with public transport or do you think you will rent a car? Bus and ferry are efficient, so it will depend on the ultimate choices if a car is better.
I would put Mostar (which gives you a sort of loop) on your list and research Montenegro more, in addition to family heritage, decide if you want mountains or sea. Also determine how much of Croatia you wish to include.

The car makes sense if you want to leave the coast. Cetinj is especially worth visiting but so are many of the small towns. When travelling around add >60% to what ever Google maps says, the roads are very twisty. SInce the country survived the 2016 (russian inspired) coup d'etat I think it is good to visit it.

As above. Tell us at which place you will meet your family and then we can suggest " the most efficient route to see as much as possible".

I agree that knowing more about your family roots would be very helpful. In addition, it would help to know something about your interests and preferred pace of travel.

I would strongly encourage you to consult a good guidebook or two, perhaps the Rough Guide. The cost will be nominal in comparison to the cost of your trip, and IME, having a couple of good guidebooks will provide a wealth of information, including answers to questions you don’t even know to ask!