Fighting Dragons
Like this I'd end vastly expanding my territory to reach a terrifying area. But that would come at the expense of wasting time. Taking control of each town or city would take at least an hour up to five according to the number of portals there.
Also if there were forces stationed in these towns and cities, I'd take time to get rid of them. Especially if they used their gates to bring forth much force.
Doing this might look great, but in the end I'd be giving those bastards a chance to slip away.
"I shouldn't get greedy," I murmured while deeply contemplating this, "towns and cities won't go anywhere. So I can just come back to them after I exterminate those bastards."
So that left two more options at my table. Either I'd scatter my monsters into teams, move fast to circle Texas from all sides and risk losing much of them during the process.