Caravanistan

Telling him that you planned to stay with Iranian friends and naming them seems like a great way to get those friends in trouble with the authorities.

Never heard of anyone registering or getting permits for places like Dashogus. If you look at the reports here, nobody has had any problems without them. Read the info here on Turkmenistan: this is what is known here.

Where did you read this stuff?

Yes and yes.

Camping is probably a better way to get the attention of police than staying in a hotel or guesthouse or whatever.

How is he going to stop you from staying in Mary?

Well, given that you need a guide to self-drive anywhere in China, I'm not sure why Tibet would be off-limits.

If you check the reports there are people who have taken the train, and many stay at the crater.

If you're doing Khiva, I would exit at Dashogus. You can take the night from Ashgabat to Mary/Bayramaly and back. Not much sleep, but it's efficient. Then visit Dashogus (people have done it by train), and hopefully add in a stop at Konye Urgench as well if you do it by vehicle.

This is quite dated, but when I was there I was able to go to a bank and get a USD cash advance from my Visa card. This avoids the exchange-rate problem. I imagine there are still banks that can do this for you, but it won't be your average bank. According to French consular services, there are a co...