Hehe, cool beans!

Don't worry about the caves. it's just WHERE you put the caves that matter. Like the cave to the left on your map is so close to the highest point of the map that created confusion, like I explained.

With a height map, there are different ways to go about one. But the type I was talking about is as simple as you use 3 base colours to just paint where your highest points on your map will be and lowest. For example. The is kind of like the blueprint of a map. You paint white to say, okay here is my high areas and grey for mid and black for the lowest, once that is figured out you can go about adding your lineart and everything. Its one way of many to go about things.

Good luck with your next map