Well, "boonies" is pretty ill defined, but my criteria is most homes are are 10+ acre lots, and large lots are widely available.

You want your datacenter to be in reach of interstate highways (rail might be nice, too), two electrical substations [1], and close to fiber that's already run. That restricts your available boonies, but there's still lots outside of the east coast.

[1] yes, you'll have onsite generation, and yes, you might plan to run from onsite generation most of the time, but you still want to have the option for utility power, and it's nice to have two substations to get more uptime, subject to more transfer switch complexity.