The MSQ will give you 645 gear coffers prior to the first Dawntrail dungeon. It will be a complete set (especially if you do sidequests, but I recall it being complete on alts that skipped them). The vendors in Old Sharlayan or Radz that sell MSQ gear will sell this 645 gear as well, but normal quality.

Quote Originally Posted by Bun_Vivant View Post
Do people think it's worth the effort to grind for 650 or perhaps better gear in prep for Dawntrail, or will the 640 gear be enough?
640 will be enough, but I would also point out that there's not much reason not to get 650 or 660, because what else is there to do? Even if you have other things to do, you can probably grind the tomestones from a few hunt trains, so may as well do it.