Welcome to the HUBB. A very general question so I'll give very general suggestions. I assume the round trip to the Himalayas was starting elsewhere in India as 10,000 km would barely cover one way to the Himalayas from the UK.

Who knows what the world will look like in 2023, but I imagine you will still need a carnet for Pakistan and India.

If you are travelling on a UK passport you will likely need to jump through some hoops to get an Iranian visa (before Iran closed due to covid you would have needed to book yourself on an escorted tour).

Don't be scared of Pakistan, in my opinion it is the highlight of the whole trip and far nicer to spend time in than India (though India has some great parts too).

Spend as much time as you can and take every opportunity to spend time with local people rather than gravitating towards other foreigners.

Don't pass through Iran in the middle of summer, it's the worst time to visit. Spring is the nicest. Autumn is fine. Winters are cold and snowy in the highlands of the west.

Don't rush through Turkey thinking it's boring because it's so close to Europe, there are a huge amount of things to see in the country, particularly if you like ancient history.

If you've not been to Iran before, ditch your preconceptions.

Just some thoughts.

EO

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EurasiaOverland a memoir of one quarter of a million kilometres by road through all of the Former USSR, Western and Southern Asia.

Yes, it was from the South of India to the Himalays and back