Question: I am a single female European and expecting to pick up my visa tomorrow at the embassy in Damascus but haven't planned too much yet. I have two options: either (most likely) I fly with Air Arabia to Tehran and back from Shiraz (or the other way round. Or to and from Tehran?). Or I travel overland from Damascus through Turkey. Which would be exciting in itself but leave me little time in Iran.
Answer: Iran is a safe country for a single female traveller. Try spend as little time in Tehran as possible and get to the cities of Yazd, Isfahan, Shiraz for some wonderful experiences. Use the planes, trains, air conditioned VIP buses. A tour group, or a guide to interpret would be most fun, they know where they are going, and especially as Iranians are curious as you are about them, and they want to hear your story, you'd miss the essence without someone to translate for you. You can spend easily 2 days in the bazaar at Isfahan alone, lots of things to sketch, and people to meet.