a) have several accounts do it, not just one.
b) Not so big a deal, pick a line in the sand and take what you can, then do the same to them, you end up even.
But you asked how to stop opponents getting to some of those villages first. There are a number of ways
1. tripwire and send a nuke and nobles when it goes off (let the enemy clear for you)
This is best for villages closer to you than to the enemy.
2. stack the villages further away from you while you eat your way there
3. if you notice the inactivity before the enemy (which you should) clear and prenoble before launching, doing this you can get the 200 villages before the enemy reacts.
Yes I have used all three of these strategies, of combinations thereof, to great effect.
c) If they are in the same place, you are going to have to accept you will lose some, but while the enemy are rapidly expanding into these players, they are also spreading themselves thin, attack them elsewhere and you can reclaim much of the lost ground.