That’s more or less what Paizo does already with their APs. They’re set in different areas, accompanied by supplemental information and options related to the area. If you are running an AP, then you can pretend the other parts of Golarion don’t exist. It’s very uncommon for APs to take you outside of their region.My preference is a detailed region that presents its information in the structure of an adventure, similar to the sandbox elements of Curse of Strahd.
It gets messier if you aren’t because there is a lot of information out there. If one is the type of person to get overwhelmed by that and maintaining setting fiddelity, then you’re going to have problems with Golarion. You can pick an AP region and ignore the AP and the rest of the setting, but it may still be overwhelming.