Kudos! Nice work!
I have two suggestions, if you want them (no criticism! Just ideas, if you still have too much free time
)
For the trend-over-time graphs (monthly cache approvals and archivals), a "color impaired" viewer (such as myself) may have trouble seeing the color corresponding to each year. Putting the labels right in the year lines would make that a bit more clear. And yes, for the record, I had to photoshop EaglEyeStash to solve it
).
For the cache density map, rather than squares, give each point a gaussian splatter, then normalize over the whole map and translate that to a color (like blue to red). At the scale you have it, a radius of 4 or 5 pixels per SD should give a nice effect.
But looks good... I never realized the NE corner of the state had so many caches.