My first map - Kyrta

[Overshee]

So I finally sat down and got started on my first map, with a LOT of help from Ascension's amazing guides. I'm pretty happy with it so far.



Of course the rivers and lakes prove to be exceedingly frustrating. First off I know very little about how they form, so I can't fall back to knowledge on that. I used some reference photos, but I just can't get them to look natural. Any advice would be awesome. My second question is about scale. I know I want it to be very large. Like, transversing the continent is a heroic task. I was thinking that villages and cities could be linked with ancient teleportation circles to make conventional travel possible and not as frustrating for players. Trade hubs and large cities would have larger teleportation circles so more goods could be sent at once or something. However, many locations would be cut off or not close to a circle, obviously, so there is still ways to make players have to work to get places.

I was thinking crossing the continent could be 3-4 months on horseback, but I have no clue how big that is, honestly, and I can't find much medieval info on such things (though likely horses haven't changed that much, still I would think that it would be a bit different). (I want to look at this from both a DnD 3.5 and real perspective as well).

Anyways, feedback and comments would be appreciated so much! As I said this is my first map and post, so be gentle