Resources aren't difficult to come by, if you know what you're doing.

17 lvl 9 barracks, que'd up in intervals of 1000 = 17 x 1000 x 9 = 153,000 troops.

Farm lvl10 NPC's a few times a day. Sell the excess food on the market, buy lumber/iron. Que the barracks up again.
Rinse/repeat.

Also, I keep my town at 100 loyalty 24/7. 0 tax. My population bounces back fairly quickly. Fast enough to load the barracks up when they're down.