Will there be building spots that are somewhat safe from giant kaijus?
I'm not sure, and you bring up an interesting problem.
Part of the game is that we're playing on the edge. We're mercenaries on the front line. There is a push-and-pushback between us and the enemy.
However, hopefully we can push a little harder and gain ground, leaving some terrain safe. Hopefully this means there will always be a forward base which is under high threat, and a base further away.. in an area we've tamed a little. So you'd have a space to go to afk, craft, be social, etc. safely.
There would maybe only be minor events quite distant from that "safer base", but the forward base would have major events closer, and possibly even have significant in-base threats.
I could be wrong, but this is how I have it in my head.