I just returned from a 11 day trip, traveling as a solo female to Sarajevo and Mostar (Bosnia & Herzegovina); as well as Hvar and Dubrovnik, Croatia. Overall, the trip went off without any major issues. First off, I personally felt safe 100% of the time thought the trip. After years traveling in Latin America for years where I've been harassed on the streets by men, I was shocked and relieved that I experienced zero issues in this realm on my trip.
Sarajevo (3 nights): stayed near Baščaršija. Absolutely loved it, fav part of the entire trip. I could have spent a week based here, seeing more of the city and day trips to nearby areas. The multiculturalism to experience, museums, market were fantastic.
Mostar (1 night). I did a tour with Funky Tours from Sarajevo to Mostar, visiting Konjic, Jablanica, Počitelj, Blagaj, and Kravice Waterfalls. I stayed in Mostar rather than returning at the end of the day to Sarajevo. I liked the tour for the most part- it was a rushed itinerary - I could have spent a half day at Počitelj and Blagaj, but at the same time, was not prepared to rent a car myself and visit on my own, so this tour was a great option. 1 night was not enough to see Mostar. I feel like I only saw the main tourist area near the bridge. Stayed closeby to the bridge, which was convenient. My general impression staying for a short time was that Mostar is overly touristy (compared to Sarajevo) with folks coming for the day from Croatia wanting to "experience" Bosnia...
Hvar (3 nights). I took the bus from Mostar to Split, then hopped a quick ferry to Hvar. I chose Hvar because it is easier to get to in a travel day in transit between countries, and stayed in Hvar Town for the amenities as a solo traveler. I chose a Rick Steves recommended apartment/sobe with a fantastic host and great spot about 10 min walk from the old town. Overall, the nearby beaches and nature were incredible, and very relaxing. It was a planned respite during my trip after more intense site seeing in BiH. However, it was also culture shock to be in what felt like the White Lotus show with elaborate destination weddings for American fraternity guys or British citizens. But the swimming was incredible, and so enjoyable!
Dubrovnik (3 nights). Took the ferry which was seamless. Loved it! So much more enjoyable than taking the bus (I got extremely carsick on the bus from Mostar to Split :( ). The city buses in Dubrovnik were easy to navigate from the Gruz port and a plus for buying the Dubrovnik pass (as local buses are included). I chose a guesthouse inside the old city walls for the location-a single room with shared bathroom (since prices are high). Boy, what it a letdown from the accommodations I had in the private apartment/sobe in Hvar. It took some adjustment for sure. But...the location was unbeatable. Overall, through, I found Dubrovnik old town to be way too touristy. I didn't feel like I needed to be in the middle of it all, as the restaurants were all geared towards couples/groups for gourmet eating- that didn't work or appeal to me as a solo traveler on a relative budget. After a half day or seeing the old city and walking the walls (which was awesome), I branched out and went to more relaxed places during the two full days I was there- 1 day I went to Lokrum Island and the other day I went to Kolocep island. I was interested in swimming, experiencing nature and seeing sites on the islands. Both islands were perfect for it, with minimal travel time on the ferries. I debated doing a day tour to Bay of Kotor, but decided against it, as I didn't want to be stuck with a large group tour and minimal time to stop at each site, with traffic. Leaving, I took the private airport shuttle for a great deal (10 euro), which I highly recommend over a taxi (can be up to 70 euro).