TC swapping strategy vs AI

So, on really large maps, playing 1 v 4 against AI on Hardest, for the most distant enemy, I usually send in a massive formation to attack. And usually, there’s a huge enemy formation which attacks my town at the same time, which is obviously almost completely unguarded.

This makes my attack a one shot gamble. Basically I have to raze the enemy town while he’s razing mine and then I need to attack his force and win.

The only way I’ve found I can better my odds is to have all my villagers migrate with my army and replace his town with a new one built from scratch, and replenish any troops I lose in the assault.

Is there another way of doing this? I’ve tried smaller piecemeal attacks and continuous raiding but it’s just so labour intensive and I rarely have good results, the AI seems to recover very well.