I haven't read that book but just to offer a perspective on routine vs go with flow.
I've always had a loose routine to my days... Go out roughly same time, baby fed every couple hours, I settled into it quite naturally.
As my son got older closer to one (now he's 1.5) I really enjoyed a rough routine, eg went out 9.30am, back for lunch at 11.15, nap at 12-2, play out at 3 back for dinner at 5pm. Bed at 7pm.
I have never found this restrictive at all. There are lots of times I can meet people.
In my mum friend group, funny enough it's those who are go with the flow, who have lots of trouble meeting up. Because it depends how well their little ones have slept, when the will be tired, they often can't commit to times or we meet and their little ones are super grouchy whereas I know my son will be happy as he is well rested.
This is my experience only but I'm happy with a loose routine. From what I've seen of GF I couldn't be too restrictive when the baby is little. I think there's a middle ground.