Greetings!
I'm currently running Mummy's Mask--love it, by the way--and while prepping for Book 3's exploration section, I came up with a question or two. Before we kick things off, please don't get tied in a knot about the 'empty hex' thing. The rules say there's no such thing, but I'm working with the provided hex map in the AP.
1) The Exploration rules in the PRD and SRD, there's a little discussion on exploration DCs and Discovery points. However, I don't see anything about the exploration DC for a tile with no specific CR/hazard. Is the GM supposed to assign an arbitrary CR to each unplanned ('empty') hex.
As of right now, I'm only seeing CRs for hexes with predefined events. What's the DC for the other ones?
2) On a related note, how many discovery points does it take for a hex containing no pre-planned events?
Use the Exploration Rules in the PRD not the ones in the SRD. The d20PFSRD rules contain additional rules from some other sources that are not from Ultimate Campaign, such as the Discovery Points.
The 3 types of locations are;
Landmark Site: The site is a large structure or sizable city that is automatically discovered as soon as the PCs enter the hex containing the site. A landmark site can be avoided or explored according to the PCs’ whims.
Standard Site: The site is not particularly obvious, and unless the PCs are traveling specifically to that site, they do not encounter the site until they explore the hex, in which case they encounter the site automatically.
Hidden Site: This is identical to a standard site, save that if the PCs don’t already know about the site’s location, they must make a specific skill check (the specific skill and DC required varies with the type of site) to locate it during that hex’s exploration.
I believe area N is the only Hidden Site on the map, so it is the only one that requires a die roll, the others are all automatically found on entering or exploring the hex.
You should plan out every hex with whatever random encounters you want them to experience as well as whatever interesting scenery is in each hex, empty or not.