The numbers refer to the Blank Hex Maps in the download section.
Pegasus Mountain is in hex #1508 (p. 2 map, 6-mile scale) of sector E5 (p. 4 map, 24-mile scale). The whole campaign has thus far occurred entirely in sectors E5 and E6.
The 1.5-mile hexes I referred to elsewhere were all inside hex #1508, and are the method I use for the lowest-level mapping.
For example, Chlodomer spent some time mapping hex #1708, and the new map was at the 1.5-mile scale. To do a 1.5-mile scale, I use the upper-left-most hex on the p. 2 map for my numbering, ignoring any hexes whose number is not inside the hex lines.
So the sub-hex-regions in #1708 look like this:
Azure Hot Springs (#1708)
All regions are thickly forested (except where noted).
#0102: High hill, can see village smoke further west.
#0103: Low hill.
#0201: Small pond surrounded by low cliffs; fed from #0202.
#0202: Narrow ravine (N-S); stream runs through to #0201.
#0203: Ravine spreads out into low area; stream runs through to #0202.
#0204: Spring #1, streams lead downhill into #0203.
Aquatic Hydra: AC 4; Move swim 120; HD 6* (48 hp); #AT 6x bite 1d10 (on a result of 1, the hydra breathes steam with that head instead for 2d6+1 damage); SV F6; ML +2; AL N.#0301: Low, extremely rocky hill; no real forest. #0302: High hill; spring #2, streams run to #0303.
Aquatic Hydra: AC 4; Move swim 120; HD 12** (96 hp); #AT 12x bite 1d10 (on a result of 1, the hydra breathes steam with that head instead for 2d6+1 damage); SV F12; ML +2; AL N. Regrows 2 heads per lost head after 1d4 rounds.#0303: Low hill; spring #3, streams run to #0304.
Aquatic Hydra: AC 4; Move swim 120; HD 9* (72 hp); #AT 9x bite 1d10 (on a result of 1, the hydra breathes steam with that head instead for 2d6+1 damage); SV F9; ML +2; AL N.#0304: Valley; Streams from #0303 continue due south #0401: Low hill. #0402: Highest hill; spring #4, streams run to #0302 and #0403.
Aquatic Hydra: AC 4; Move swim 120; HD 7* (56 hp); #AT 7x bite 1d10 (on a result of 1, the hydra breathes steam with that head instead for 2d6+1 damage); SV F7; ML +2; AL N.#0403: Steep hill; stream runs through to #0404; waterfalls. #0404: Low point; tiny pond; fed from #0403. #0502: Hill. #0503: Hill.
All four springs are driven by deeper cracks and caves running through the limestone and granite to the subsurface magma in this region, and are connected at the deeper levels. The deepest waters are extremely hot! The springs themselves resemble this rainbow geyser (although they don’t spew up very often).
I’ve deleted the treasure entry because the players haven’t managed to track it all down yet.