I like a lot how this colony worked out:

1. Map has big enough mountain to have everything behind thick layer of rock, which makes breachers "breach" through killbox.
2. Map has convenient "area revealed" that is not too far from colony center and not too close, and with space for everything.
3. Happy with how room layout ended, very optimal. 4)Figured out perfect workshop layout.
4. Finally did two things - collected all 3 relics and about to get archonexus ending.

And i find it interesting to compare with what i counted as efficient and well-defended colony in times of 1.0:

https://www.reddit.com/r/RimWorldPorn/comments/eyoona/boring_efficient_vanilla_base_for_merciless_randy/

And have to say, with DLCs colonies got like twice bigger and it feels great.

Easily? I dunno what happened in last versions, but infestations are joke comparing to other threats, they just not as big as before.
Other than that, just usual melee blocking at chokepoint tactic.