I have spoken a few times with https://www.miltours.com,
and they are looking into a trip to Midway Atoll in mid-September.
Interesting, Michael. I've been keeping up with the miltours website, but I hadn't signed up for their E-mails, so I didn't realize they were considering a trip to Midway this September. I'm definitely interested in that, too.
As for the question winterkjm posed, my nearest-to-home WHS that I haven't visited are a set of three in Atlantic Canada (Grand Pré, Joggins Fossil Cliffs, and Miguasha) and the cruise-friendly St. George, Bermuda. I have no doubt I'll get to those sites, but it really comes down to a balance of vacation days during the year, and, depending on how many vacations I schedule a year, money.
As winterkjm pointed out, for those of us based in North America, the majority of our WHS require either a plane flight or a long car trip, which limits the average American traveler. For those of us who do travel through sites in North America, our WHS-visited craters on our profile pages aren't really as impressive as our European counterparts, since North American WHS are spread across such vast distances.
I do hope to hit every WHS in the US and Canada at some point, but it will take time, particularly with some of the more expensive trips like Nahanni National Park and SGang Gwaay. The number of sites that Gary has visited in Canada and the United States is very impressive, and would be about on par with someone who was able to complete Russia or China.