Hé buurman
Good choice. We stayed in Iran for almost a month in August of 2016. We liked it a lot and I am sure you will too.
1. We have no experience with Ramadan while being in a predominantly muslim country. What I've heard is that the sick, the pregnant and travelers are exempt from the strict Ramadan fasting rules. Nevertheless, I would make sure I'd leave every morning with sufficient food to last until dusk and not eat in plain sight of other people during daytime.
2. The shortest route from Amsterdam to Istanbul is approx. 2750km. That's less than 3 easy riding weeks. I suppose you could increase you daily mileage *a bit* in the first days because you'll be able to visit these places again when you're back. If you take a bit of a meandering route through Turkey, instead of going directly from Istanbul to Iran, that'll be another 2000km or more. So say it's 5000km from Amsterdam to the Turkish/Iranian border and you're riding 5 days a week, you could still make it by late april if you do only 150km per riding day on average. The transit routes (non-motorways) in Turkey are in really good shape, so you could easily do more if you wanted. I think it's important to take it easy so you don't *need* to ride if you've found a nice place and want to stay a few days longer.
If you decide to take the more southern route, you will be crossing the Alps. Inform yourself about the situation on alpine passes. Many are closed during winter:
https://www.tcs.ch/de/tools/verkehrs...uelle-lage.php
https://www.oeamtc.at/verkehrsservice/
Eastern Turkey has quite some elevation (well over 2000m above sea level in places) so get information from the locals about the road situation. It's quite far south already (from our viewpoint anyway), so the weather might be no problem anymore in April.
3. (There was no number 3, but now there is :-)) The border crossing from Turkey to Iran at Bazargan has a bad reputation. Don't let yourself be put off by this. Iranian hospitality will soon make up for it. The trouble with this border crossing was not the immigration or the Carnet/customs, but the insurance guys who team up with the border guards. They claim that they can only let you go past the final barrier into the town of Bazargan if you buy their expensive insurance, which turns out to be exactly €100 (what a coincidence, aye?). You can get around it by
driving them nuts for 2 hours until they are sick of you, but I recommend the following:
Because you know approximately when you're going to enter Iran, find an insurance company that will extend your 3rd party vehicle liability insurance ("W.A. verzekering") for Iran for the time that your visa is valid or for the entire trip if that's easier. If you can show proof of this insurance at the border, they have no good arguments anymore to sell you an insurance. And if they do, keep arguing.
I think it is best to ride all the way up to the barrier, keep your engine running and your helmet on. Show them your extended green insurance card for Iran (or rather a good color copy) and say "I have international insurance" as many times as necessary for them to have enough of you, have them stamp the white paper slip you were given at customs, and have them open the barrier. Welcome to Iran!
Enjoy! Let me know if you have a blog or something where we can follow you. If you have any more questions about Iran, don't hesitate.
Cheers,
Mark