Welcome to the Mirkwood World Expansion Project
Use a grid spacing of 4 rooms per square, I think that makes for a large enough world. Comment if you think the spacing should be larger/smaller.
As far as landmarks go, just grab a map of middle earth and use that :) We'll have to pick names for stuff once we start on the Theran continent. Also I'd like to split Elacia (east continent) up into three areas, western, central, and eastern Elacia. All the rivers and connective roads will belong to these areas. So talk to me if you want a whole section, or just a river or road or whatever.