Okay, I have slept on it and thought it over.
The most crucial project is the Granary. It provides everything we need: protection for the excess food we are producing, permanent Manpower and Fields upgrades (which will improve food production and, most likely, give permanent manpower).
Granary is the project that the winning plan must have. The info on the Fields upgrades, in particular, is required to properly plan the projects needed to reach Hamlet.
I had wanted to do Center now, but I had underestimated the Hamlet requirements. I had thought we would need like 5 permanent manpower and to produce both Agriculture and Material. But I was wrong.
We need a whole 8 permanent Manpower, which is 6 more than we have now. That means we simply can't start the advance into Hamlet project right after building the Center if we start it now.
That lives us with two options.
We start building the Center now and get 3-4 manpower while we finish it (as Quarry and Docks don't give any). Then we spend 1 or 2 turns getting the manpower we are lacking before doing the Hamlet project. Those are turns where the Center is just there doing nothing.
Really, the Center doesn't gives us anything we need. It gives Administration, but we are already at 100 and we aren't reaching the next bonus just with Center and Granery (they give 15 and we need 25). In fact, Center just offset the Administration penalty of becoming a Hamlet.
It gives defense and unlocks Palisade for even more defense. But after the Summit the squad will return and, unless something serious happens, at least a couple of people will be at Snowblossom. So the defense will always be at 100.
The Center's main appeal is to become Hamlet. So we should coordinate to finish it the same turn we get the 8 permanet mapower, so we can start the Hamlet project immediately after.
So the second option is to do Granary (as I explained it above) and another project now and then start Center the next turn.
That is objectively the better option.
So the question is what should be the second option.
I really wanted to do Quarry so we had some source of Material. But permanent Manpower really is the top priority.
Then, Docks is the best next option, as we'll be able to do Boats and learn which upgrades come next.
Now, Pastures could also serve. But I would rather leave any event, no matter how "minor" for after the Summit. The Snowblossom Meditations project won't be a problem if we don't take it. Which we can do right after the Summit.
Though we are already here...
Manning all of our infraestructure is also a problem. We simply can't have everything at full throtle before we reach Hamlet.
So the optimum solution is Granary+Docks then Center+Boats and we'll se from there depending in the further Fields and Fishing upgrades.
[X] Plan: Funny name
-[X] Subsistence Granary
-[X] Fishing Docks
[X] Plan Don't Run with Scissors
-[X] Subsistence Granary
-[X] Subsistence Pastures