The answer is, Yes! It is completely safe for solo women travelers. I spent quite some time in El Salvador and had the time of my life!
When I was initially researching El Salvador, many associates told me I should not go because of the reputation and crime rate. After doing my research, I decided to go and I am so happy that I went!
Where did I stay
I stayed in quite a few different areas in El Salvador. My favorite neighborhood was San Benito! It was very safe and close to shopping centers and restaurants! I will do a series of different hotels I stayed at, as well as compare them. I walked around San Benito it was very beautiful!
Safety
I did not ever feel unsafe. I felt very safe! Of course, use common sense! I blended it well with the locals. I did not walk around with my phone out. I always mapped in my head where I was going and if I needed to use my phone as a GPS, I would pull over to an area where I can concentrate. I wore casual clothes, no jewelry, and no headphones.
I recommend purchasing a portable lock so you can lock your items in your suitcase. I do not recommend using hotel safes as they can reset the code and steal your belongings. This can happen anywhere! None of my items were stolen but I always like to take precautions.
Transportation
I either walked or used Uber. Uber was very reliable and extremely affordable! I used Uber to get from the airport to my hotel in San Benito, El Salvador, and paid $33 USD. That was quite a bargain considering how far away the airport is away from San Salvador! Most of my Ubers were 10-15 minute long rides and cost no more than $4 USD each way. Very, very affordable and my preferred way to get around the town! I never took a bus or cab so I am unable to inform you of those prices. I did hear most fairs for the bus start off at about 25 cents USD.
Currency
The currency used in El Salvador is USD or BITCOIN! I was so shocked to finally see Bitcoin somewhere. I saw it advertised quite a lot out there!
Final thoughts
Keep in mind that most speak little to no English. I highly recommend learning a bit of Spanish before going! I went to quite a few local restaurants where I did have to use a translator in order to eat and order. Most of my Uber drivers did not speak any English so have your translator ready! I recommend downloading the Google Translator with the voice option. That way you can record what someone is saying and listen as they speak.