Seeking advice on driving to Mostar

I also drove in BiH, and it felt perfectly safe and I had no problem navigating. It's really no different from driving in Croatia, except the signs have both Latin and Cyrillic alphabets. I drove from Plitvice to Sarajevo, then to Mostar, and then to Split, with a stop in Pocitelj, which I agree was worth a stop. On the drive from Mostar to Split I took some back roads and detours so I could see more of the countryside and some smaller villages. It was delightful. Tell your husband he has no reason to be hesitant.

Thank you both! I've read that some car rental agencies are less likely to rent a car being taken into BH, any suggestions as to which to try? I alway book online and arrange the car before I leave the US. I don't want to find out that I can't take it in to BH.

If you decide against driving, I want to offer up the bus alternative. It was cheap and easy. I'm not sure how you can drive "into" Old Town of Mostar because it's heavily pedestrianized, so I think you can park someplace close by right outside. I highly recommend staying at the very lovely Muslibegovich House which is part hotel and part museum and is absolutely gorgeous and serene. I think I found it and booked on booking.com although you can book directly too.
http://muslibegovichouse.com/

I think the one thing that makes people nervous about driving is the sign about land mines, but frankly the roads from Ploce to Mostar (the only ones I'm speaking of) seemed fine from the bus and you're very unlikely to hit a mine unless you go off the beaten path.

The only way you'll know whether taking the car into Bosnia is permissible is just to make sure to read the fine print. I bet many rental companies will have this restriction..maybe they're worried about perceived increase in theft probability or car damage from potholes which I'm sure are the case on smaller or poorly maintained roads.

I worked with a travel company to organize my trip for me, so they made the rental car arrangements. I don't know what company they used.

I also stayed at Muslibegovic House and loved it. They provided free parking (not on premises, but about a half block away). If your hotel has secure parking, I'm sure that will work fine too.

Thank you all so much for your advice and encouragement! We will definitely drive to Mostar. It sounds like we would really enjoy seeing the smaller villages and the countryside as well. I think we will head to Mostar from Metkovic, and when we leave town we will take a different route on our drive to Dubrovnik. I don't have a good map of the area yet, so if you have any advice to offer regarding specific maps or routes I'm all ears!

Freytag & Berndt are the best maps of Croatia and Bosnia that I have found. Do check the publication dates though. Some have complained about particular online retailers selling old stock.

Just make sure ahead of time that the car rental company will allow you to cross borders. Otherwise, the drives are easy and scenic.

Terry,
Drive...do not take a bus. All rental agencies allow you to drive into BiH but you must tell them up front so they include the travel papers required for border crossing.
Take your time and stop in the small villages along the way. Everyone we encountered was very friendly.
Make sure you have some euros or convertible marks before crossing. We didn't find any ATM until we were at Mostar.
One note: Bosnia is somewhat more conservative. So bring a shawl or better yet, buy one at a local market. We needed one in several places to cover bare shoulders. It's an amazing country and we can't wait to go back!