First off lots of words ahead:

From all the bases I have made ( military outpost, firehouse, firelook, evac shelter, one from scratch) I take location into consideration.

So for example, in the current game I have a fire house base that is close to exodii and evac center, next door to a home improvement warehouse ( really nice when I started to build expansions as it has a lot of useful stuff and construction material bundles- got 200000 units of cement from the cement bundle), has potential for me to dig down and access the railway system and sewer system and since I cleared it out in year 1 spring, I have an easily accessible supply of a lot of random stuff from disassembly.

Since I have played around start near an evac center, makes a lot of material available and makes vehicle construction a lot easier as I can just trade some high value items and get most of my vehicle gear from Smokes ( welding gear, rods, tools, etc)

I found the firehouse is probably one of the quickest bases to get up to basic function, fairly secure as it only has one entrance room plus the 2 garage doors. It is limited on its funtionality and a bit lean on storage space it makes a fine compact base.

Military Outpost bases can be really secure as it only has metal door entry, and you can make your followers make a defensive trenches around the bases, also because it is built in the wide open you can see wandering hordes easier.

I find the moment I make an anvil, is the point where I can move from survive to thrive