What your asking for is kinda state of the art. You want very high res maps that have good or at least believable geology but in a package that makes them really easy to create.

What you are looking for depends in what your looking to trade off. I could say that I know of some apps that would get you what you want but need a lot of effort. You can get a simpler, less accurate terrain much easier.

I write a suite of tools called GeoTerSys which could produce great output and do exactly what you want, it is not very easy to use and does require some setup time. Its a scripted app so that when you get your scripts right, its a quick sketch for the initial input, a button push, a long wait for a CPU chug and then out pops what your asking for. I don't think its the app you are looking for because it takes too much effort right now to set it up though it may be that in a while the interface to this sort of thing becomes more intuitive.

There is another app I know which does kinda similar and would probably be suited to your needs. Its pretty easy to use and pumps out large terrain. It is my opinion that it is less geologically accurate and lacks some abilities which is why I chose to pursue my own app but you may find it suites your needs well. It is L3DT (http://www.bundysoft.com/L3DT/).

Now no app that I know of produces cities and towns that have any kind of realism. Its too much of a human guided process.

First of all lets consider the terrain resolution that you would need not to be pixellated. I would suggest about 5m or maybe 10m. For a 1000km map that would be 100000 pixels square which would fill a medium sized harddrive.

So you need terrain that has several levels of detail - what we called LOD's. You need a planet, you need a large scale map, some smaller regional maps and then some town and maybe a battle scale map.

How you create these maps that fit together without the tools I am writing I dont know. Thats my quest to solve that issue. My GeoTerSys suite is a procedural zoom based terrain generator so it can generate small sections of a larger map at progressively higher and higher res. I know thats what you want - its what I want too.

Right now I would suggest you get an app to create the large scale terrain like L3DT and generate your world map based off of that. Also base your regional maps off of the that terrain map too but not in an automatic kind of way, just make the terrain large enough that you can do a half decent job.

For the town, floor plan and battle maps I would suggest you continue with hand drawn maps and scan them in. This is again a trade off between how nice and how much time you want to spend doing it.

To manage all of these scaled maps I can definitely give you a solution. The other mapping program I write is ViewingDale. Its a zoom browser for multi scaled maps. Basically you put all the maps of all different scales into it and it will draw them fast with pan and zoom. When you zoom in from planetary or large terrain onto regional map then that one will fade up and be synchronized to the larger map and you can keep going in right down to characters eyebrows. You can then print out any part at any scale or res. It allows you to put symbols down. You can import your own symbols or use the ones provided. You can also add text, pics, docs, movies, sounds etc to the maps too.

Theres a demo from the link in my sig and if you can wait till March 2008 then there is the iCon 2008 convention which is an online get together for mapping and virtual table top apps. You can always mail me for more info if you feel like it.