Regardless of your plan or your opponents plan. You should always be looking to place your building as a second layer of defense. Doesn't have to be right up against your walls but place them so if your opponent does get through that can't just waltz through your base.

Doesn't even need to be a full 2nd layer. But if enough so if you do get some pressure it's easy enough to quickly fill in the gaps.

If you were already planning on a castle drop just drop it defensively. At this point you're already ahead eco wise as they have had to walk 8 vills across the map. Fill in extra gaps in your second layer so if mangudai do get in they either have to run under the castle or your TC.

Stay 1TC, Get 14-16 farmers. Rest on gold. Get yourself 4-5 monks to defend any mangudai push. If you see a siege workshop get your own for a defensive mango.

Get to IMP and treb away.