I backed Mike Shea's last "campaign" type book, and it was a great setting and collection of adventures. It was designed for levels 1 through 5 (similar to Lost Mines of Phandelver), but then at the back he included an appendix with ideas for, IIRC, a level 5-20 campaign. It wasn't super detailed, but it was enough to give DMs an idea what to do if their players really liked the setting and wanted to stay down there.
You know how you can read a campaign book and be like, "Why is this so confusing and hard to understand? Don't they care how hard the campaign is to run?!"
Well, Mike does care -- that's his whole shtick, so I'm definitely going to back this.