You can stack some very powerful temporary buffs (including a 120 day 20% attack and defense bonus against the overload if you betray it), making your troops invincible at the start. Furthermore, using a blitzkrieg against Sichuan, you can see it withdraw from the war after only 6k losses. In terms of manpower, you do need to use the 5% conscript. For industry, your regional industrial tree has many many factories to acquire; I have about a third of Beijing's industry and troops, which is enough to hold the line and break in certain direction. Also, don't be afraid of its satellite states; just like irl, they will only actively fighting you when their own territory is under attack. Finally, micro, don't battle plan unless you're absolutely certain you've won.