Well, in the game we play, the overland speed of a horse is considered to be 35 miles a day on average, assuming 10-12 hours on the road and any rests needed, etc.; so by that figure I suppose the map would be roughly 1250 miles wide (and tall since it square) - but this is meant to be a vast area which is only mildly civilized...that was intentional. There are small unmarked homesteads, farms, etc. to be found pretty much randomly between the noted area on the map.

As to the river; well it was initially going to be one of a pair of rivers that came from the mountains, which joined quickly on lower land at a lake, and then continued on the course you see. However lack f time (I was working on this in the final hour before we started the game) and lack of a steady hand with my mouse led to what you now see. I suppose I could revise it; it was intended to be representative of the pooled knowledge of the 7 members of the group when they met an sat down to figure out where they were going - it could easily be said that one or more remembered things incorrectly, and fix it on an 'actual' map. I would welcome any advice on making it better!

Thanks for all the input so far!