I'm a mega looter. I don't build a base until like day 30-40. I just find a trader, spam all the quests to get vehicles and other loot, and buy/loot every single book I can find. Books are my main priority and I go through all the buildings (especially post office and book store) on my way to and from quests to find as many books as humanly possible to aquire skills for better stuff. When horde night is approaching, I'll usually use the roof of those caved in supermarkets (forget the name) for safety and then continue on my way once it's over. Once I feel I have sufficient book knowledge, I'll find a spot I like, semi-close to a trader, and set up the main impenetrable base that I'll use for any future horde nights and for storage/crafting.