I found a stone field eventually, though it took some fighting, and proceeded to conquer the map. Another tactic I like is to eliminate some spawning points, set up a defensive perimeter near my base - with those cool towers - and then go round the enemy's attackers using alternate paths cleared when I destroyed those spawning points. Then I destroy his base while his troops are away and being slaughtered by my defenses (Windarchers with Icestrike rock!) This is why this game is so good - you can use real tactics, and you have to avoid being seen, and if you are, you have to make sure the scouts don't get back to report about it.
I haven't found all the Elven building plans yet, so I can't summon Druids and Elder Druids yet, but I always research all the upgrades before training units. In fact, I sometimes go so far as to defend my base with my avatar alone, and not build any Rangers or Warders, but wait until I have Windarchers and Protectors.
I'm a defensive gamer too, but I try not to clear the map before I activated the monument. I prefer to build my base while fending off enemies. Then, when I have Windarchers, I position about 30 of them in a line, with some Protectors in front, and then I lure the enemy out with my avatar. It's cool to see how the opponents get turned into a pincushion before they can say 'Take cover'.
