to get all this even close to realism, you would have to study the entire road-network of the time in that particular area, and then you would have to make up a sophisticated weather system, to simulate road conditions (which is probably the least of the problems)...and the rest summarizes in: the genius of the CinC, to spread his forces wide enough in order to render quick movement possible, maximize the use of good roads, yet not to get them crowded, and then keep the forces close enough to be able to concentrate them for battle (a good and obvious example would be the campaigns in the American civil war, where many battles were fought over road junctions...), and not let them be defeated independently...only few have achieved this - and those became the few famous generals we remember throughout history, Napoleon was definitely one of them...These considerations are the most difficult to consider, when in command, even nowadays with different parameters...so in a game it, if you played it realistically, which I believe you did, it's absolutely normal to have the problem of being outnumbered...this is where independent command and rear-guard actions become the most valuable...
I know that most of you already know the stuff, I just mentioned...
For myself in theorie the best combination would be "1813" and HWLG although I know it's not possible...)