in case you want to use something other than hex maps, here is a lovely collection of maps for most napoleonic theaters:
http://www.murat.ca/maps.htm

You can also download the maps for t 1809 Danube game from here:
https://vassalengine.org/wiki/Module:1809:_Napoleons_Danube_Campaign
 

I use the layer approach when creating maps. PowerPoint is one possibility, though the same principles apply with other dedicated tools (mine is currently Pixelmator Pro on the iMac). Previously I used Microsoft PhotoDraw, which was available for free but had to be used with an emulator as it is a Windows OS application. 

The basis for my maps is a 4x6 grid. Each square in the grid represents 1x1km. This gives me the groundscale. You can create a hex-based grid as well. I then import the tiff, jpeg or png image of the source map. Alternatively, a screenshot of the area of the map that is relevant can be pasted as a layer. You then push the map image backwards until it sits behind the grid. This will enable you to resize the image to the groundscale. From there it is a case of layering on the roads, rivers, woods, towns, etc. 

Here is an example:

Robert

Little Wars TV has two free downloadable ACW campaigns - Vicksburg and Gettysburg. The overall topography on the maps is relatively simple, so when forces meet you need to fill out the battlefield. Counters, cards etc are all provided in the free download availabe from this site:

https://www.6mmacw.com/

Hey guys, the links and advices are increadibly helpful, and some awesome maps too! Thank you very much for all your help, I really appreciate it.