Has anyone moved all there settlers to one location? It sounds easier to maintain but I don't want to do it until I know more

It depends. If you have a lot of settlements established, you probably can't move them all to one location. The 'official' size limit is 10+charisma. So if you have, for example, 7 base charisma, and an outfit that gives you +4 charisma that you're wearing while hanging out at your settlement, you can create a settlement population of 10+7+4=21. If you have 10 base charisma and a +5 charisma outfit, you can get 10+10+5=25 settlers, and so on. Given that you probably have at least a few settlements established, it isn't likely to be possible to send them all to one location.

There are possible combinations of outfits and various chems/drinks that can give you a temporary charisma of around 30 as I understand, though I haven't tried it. This would mean you could hypothetically send a total of 40 collective people to one settlement. However, again, it's likely that you have more total settlers than this.

Simply put, it's not possible short of simply shutting off all of the radio beacons and "disbanding" your other settlements.

Some of the settlers can not be moved to another settlement.