Book 2 is very sandboxy, but I don't think it really warrants exploration in that sense. Meratt County seems fairly well-charted, with roads and signage (however poorly maintained). Our group stuck to the roads except on one or two occasions for the duration of the book, and it still took us almost a year to get through the book. (We also had almost no random encounters.) I can see the merits of hexploration, but there's already plenty to do, especially if the group leans in on the roleplaying and semi-kingdom-building-lite of Stachys.
The best use of hexploration imo is if they really want to explore the Void Wood, Lionsmane Forest, or the Beggarwood. If you want to throw in some of the extraneous locations (Cascina, Ralthorn Manor) and let them stumble on them as a result of exploration, that could be fun. (I built up Ralthorn Manor as a location, and I still hope the group eventually decides to go there.) But the idea that Lotheedar, Pensaris, Moost, Voinaris, Stachys (and even Sotto, Jambis, or New Towne) would require any more than just following the roads seems a strain on credulity at the least.
You could make your own, of course, but someone has already done the legwork: https://www.reddit.com/r/Pathfinder_RPG/comments/aqntdo/i_made_a_hex_map_of _taldor_for_my_war_for_the/
