Well assuming Sony Pictures Television are still the production studio, looking at where they shoot there other “period” shows might be a good indication of where the bulk of the filming will occur.
Outlander uses Sound stages in Scotland for there set work, and The Crown is based in Hertfordshire England. Both are close to plenty of appropriate outdoor settings as well. Narg would be surprised if the show isn’t based in Britain or Europe somewhere. Which ever country gives them the biggest tax breaks/incentives/funding grants will likely determine the base though. The forests, old villages, castles/manors and ruins spread throughout the UK and Europe are suitable for most of WoT’s settings.
The Waste is the only setting that they might need to travel outside Europe for and Morocco is a popular filming location for desert settings.
The best setting for the al’Thor farm Narg has seen is this place:
Throw some thatch on the roof and it’s perfect…looks just like Narg remembers it…
For Caemlyn, perhaps parts of Edinburgh for the inner city and Palace?
A bit of sprucing up with cgi and Edinburgh Castle should come up looking nice.