Please keep this as spoiler free and try to avoid specifics as much as possible.

Other than taking the castle, all I have done for the minute men is capture more settlements and ignored the repeat quests. Do things ever pick up for my career as a middleman minuteman? Will different new MM quest pop up as I go through the main story, do I need to capture the remaining settlement or two, or is this all there is until the end?

My progression(spoilers ahead)

Thank you in advance and please try to avoid spoilers.

Your on the right road , do that and you will get some different quests to do .. when you get to the molecular quest it picks up alot and things will change . but, those mm quests of a settlement needs help , really never go away / if it isn't mm is someone else . never know a settler may need ur help ..

make sure _ _ _ _ _ _ is fortified well .. I interacted with the other factions and had a nice variety of quests to do until the end game was happening then is all ' optional to you '

have fun , I did

Thanks for the reply.

Yes you're on the right road, but, to be honest. No, they never do really pick up.

Think it settles down and picks up. But not sure doing different choices this run through so well have to see myself.

...but you're already a General. Surely you must be satisfied with your career, and the quests worthy of a Minuteman General, no?

After many hours of play I finally decided to move ahead through the main quest.
(Something about turning Level 50, made me feel old!)
So I decided to move ahead, with the Minutemen.

Without spoiling, we're deep into the exciting climix to the adventure, the story, an explosive moment in fact...
This guy Garvey and I are standing there admiring our work, feeling the enormous relief of accomplishment. Pretty amazing.
To finish up the main quest, it says to speak to him.

And he says: "heads up - settlement is being attacked by Ghouls! Better get down there and help out. Always try to be helpful."
LoL, heheh...
Right in the middle of the big story climix, yeesh!
But he was not done! ANOTHER settlement is "having problems with Super Mutants".

Oh, man - so much for my enjoyment of the Main Quest...
(Because, tick tock, I guess it's 'over' now, right?)
So: does this guy Garvey EVER STOP? The answer is no! Most definitely no, he never does.

LOL, yup, that is pretty much how my "ending" played out... I was hoping for some epic words to wrap it all up, but nope, first I have to listen to the settlement attack routine, before I can finally talk to him about what just happened!

Geez, I think I'm blocked at about the same point. I'm about halfway through to that explosive moment with the Minutemen, and at this point I need to speak to Preston to trigger the next step along the way.

What happens? I'm given a Ghoul cleanout quest - right in the middle of this epic mission! Are you serious Preston - right now, really, right now?

Not only that, after he gives me that quest, he no longer responds to me - just the typical responses when an NPC has nothing else to say. So I'm blocked.

DAMN YOU PRESTON!

The Minutemen have far fewer faction quests than the other three factions do. The only 'main' Minutemen quests are When Freedom Calls (the first one in Concord), Taking Independence, Old Guns, Inside Job, Banished from the Institute, Form Ranks, Defend the Castle, and then the Nuclear Option. A lot of these quests are rather lackluster. Depending on when you do the first few Minutemen quests, the Minutemen quest line may come to a grinding halt for a really long time since everything after Old Guns only becomes available after a certain point in the main quest line. The bulk of what you'll end up doing with the Minutemen faction is the settlement stuff and radiant quests.