Interesting! We don't see too many maps of this time period around here. I think the pixelation is a pretty big issue in this map, if you can fix that somehow it would be a big improvement. I don't know how one does that in CC though, so I'm sorry I can't be more helpful there! I'm not sure forests would be shown on this type of map, I may be wrong but it feels like streets would be of higher priority, and the rural parts could be left blank except for the height lines.
Kudos for trying something unusual!