Two factor authentication when changing countries
I'm about to relocate from one country to another. This will mean I have to change iCloud accounts as the address on my credit card will change. Also, I will have a different phone number and will not have any of my trusted computers with me as I intend to buy a new one.
So how will my two-factor authentication work? How will I get into my iCloud data?
I appreciate all answers but it would be great if you could include links for your sources (e.g. an official Apple support page)
MacBook Pro, macOS Sierra (10.12.5)