I looked at your docs.google map, and I think you might be able to use another color for the non-grassy bit where the trail goes into the cave -- or not, because that bit is less than a square wide according to the map-fragment you posted. (Eddicus should be sort of near H-18 or I-18: out of sight behind briars, but within a single turn's speed of engaging in melee with the foe.)
On a completely unrelated topic, here's another question: if you have the DMG, do you also have the MM?
The reason I ask is that I'm trying to conceive of a 5E human druid as a thought-exercise, but his name keeps trying to be Sedgewick Conchrain.
OK, he might eventually be able to learn "Conjure Animals" and cast that spell to make it Rain Conchs; but what are the stats of molluscs in the MM? (I'm guessing there aren't any. . . .)