I will be flying into Shanghai, arriving late at night, and am thinking of taking a train to Lhasa. I only want to spend two nights in Shanghai.

Can I buy the train ticket and the permit in that time ? Should I buy the ticket now on the internet ?

I hope to arrive in Lhasa and climb some of the treking peaks nearby. I have (18) days there. I also want to hire a guide/itinerary to visit Everest base camp.

Is it also possible to just hire the guide once I get to the city?

Thanks for your help.