Going on a tour of Iran and Turkey is an adventure. I didn't have any experience of countries where Islam is the cultural norm. Everything is different from what I'm used to: lots of tea in cafés and "bars", not so much beer (better in Istanbul than Tehran, granted); mosques everywhere instead of churches; water jets rather than paper in the toilets.
This last was the most difficult to manage. I had read about the phenomenon and brought the necessary materials (wet variety in a resealable pack). But it turns out I didn't need it as much as I expected. The facilities are mixed, traditional and "western". And in general very clean in both countries.
Here's a tip: next time you're driving between cities in Turkey and you're looking for a place to stop to powder your nose, look out for a chain of service stations called Opet (written with a stylised initial O); they proudly boast that they have the cleanest public toilets in the country.
I've tried several. You can trust them.