You can use a strategic game like TOAOW to keep track of units & use a lot of its rules i.e movement supply or simplify them a bit. As this lists units in each formation tanks AA AT etc using the editor to quickly adjust at end of each battle is generaly good enough. Okay you abstract a bit unless want to keep a spreadsheet & record in detail, got 7 AA units left for example doesnt tell you what but just abstract from full strength unit. Easy enough to keep tabs on diffrent formation types tank mech etc & types 1st 2nd line. Playing even a small front like this though you will lose a few years of your life
Important I think to make the game work is R&R to easy n game just swings back n forth, to repair units really need to come out of the front line abstarct it by saying if attacked while doing R&R 1/3 of units cannot take part. Also using something like if reduced below 40% disbanded enter reinforcement pool makes things easier. Treating citys as resource makers gives a reason to take them to citys "producing" your R&R points dont all have to produce the same making some more important than others, lose that city you lose its R&D points so things get tougher.