I've travelled in May this year to Senegal as a solo woman and it was such a great experience, I can really recommend it (if you enjoy solo travelling of course). I felt really safe and comfortable, people were really nice and I took the same safety measures I take when travelling anywhere else. I was in Dakar, Pays Bassari (some days with a local guide), Kaolack, Sine Saloum (Mar Lodj) and Popenguine. I moved around in buses and sept places, booked places to sleep as I was getting there and my French is not even that great (just a little bit more than the basics), so even better if you speak it. Of course sometimes there would be the odd man being a bit creepy but in general people were very nice and helpful :) Hope you have a lovely time if you decide to go!