So I can really only speak on KCOM, because thats what I know.
Let me address your concern about USMLE first, because it seems like this is important to you.
Every single one of my friends who I hang out with regularly is taking USMLE and COMLEX. I am not, because I plan to try for a less competitive specialty where USMLE is less heavily weighted. But even one of my friends who is thinking family med is taking USMLE. The way the school teaches it, as well as just about every other DO school across the country, you should be prepared for both by the time you're done with two years.
Now about some of your other points, and some of my own personal talking points.
Over my past two years at KCOM, I have really enjoyed my time. I really liked most of my professors, and the ones I was less impressed by have just been shown the door (seriously, they were finally canned). The biochem department, which was originally probably the weakest aspect of the curriculum is being revamped by a guy who is really well respected by students here and someone whom I believe will do a great job at bringing it up to the level it needs to be.
KCOM has a course built into its curriculum called, "MEDI," which is an internal medicine course. Basically, they have doctors come in and give lectures about different disease processes related to the system you are currently covering in your block. It's a pretty tough course, but when you're done with it, you can really come out looking like a rock star in your rotations. Plus, as you work through it, you figure out how to prepare for it and what kinds of things will be tested, and it gets "easier."
Additionally, the anatomy department is PHENOMENAL. I know you weren't really wondering about that, but it's awesome. The anatomy faculty are wicked smart, love their content and love their students and it is evident every moment you are with them. The cadaver lab time is incredibly valuable if you want it to be, and you will come out knowing your anatomy well.
Housing is great, almost anywhere in town is within a 5-10 minute drive. Some of my friends have one bedroom places for $450/month, and some of my other friends share a 3 bedroom for $750 a month. There are options for just about whatever works for you.
Regarding the alumni network, you're spot on. There are ATSU alum EVERYWHERE. And people really respect the ATSU name. There is currently a spreadsheet floating around that gets passed from class to class with names, email addresses, residency programs and "current" employment of alum where if you have questions for someone, they will take your questions, whatever they might be. Also, some of my classmates went to conferences, and when they introduced themselves and where they were from, they received an immediate level of respect (can't speak on this from my own personal experience, but it was from a pretty reputable source, so I trust them).
Regarding your points about town size and remoteness, I cannot argue with you one bit. You will definitely begin to miss your favorite restaurants or your favorite stores to shop at. So for me, that was Culver's and Costco. But that just meant that whenever I drove home, I'd have Culver's on the way home, shop at Costco and then have Culver's on the way home. You can definitely survive without those things, and then whenever you do get them, it makes it more special. As for remoteness, the airport in Kirksville has hopper flights to and from Chicago for ~$60-70 if you book early, which is frequently used by my peers. I guess if I were to leave you with one last message on the topic it would be this. As I was driving home today after saying goodbye to some of my friends who are moving away for rotations, I was incredibly saddened. I truly believe that the community that is fostered by the school and by all of the surrounding factors such as the town being small and remote lend to the formation of bonds between your classmates that are honestly strong enough to make up for some of the other things the town might lack.
Depending on where you live, the clinical sites can be great. I'm sure you've probably looked into the sites so I won't reiterate those facts, but if not I would be more than happy to answer any questions. The basis of site selection is somewhat weird. It's a sort of lottery system based on ranking lists, it's pretty complicated, but for the most part people get one of their top three options. For my class, I think something like over 90% of the class got one of their top three choices, so in the end it works out pretty well for mostly everybody. As a class, people tend to work things out and if youre vocal about where you want to go, it tends to work out for you.
Regarding OMM. Uggghhhhh. It kinda sucks, but just because it takes away from your other classes. That being said, I'm really not doing a ton of study for COMLEX, because the way the curriculum is set up, they bring back relevant information periodically so you don't forget stuff. But it still sucks... Those are the negatives. The positives are that the faculty know their OMM and you know that you are learning from the absolute best of the best. Not to mention the fact that they are all super kind and helpful during lab times, they want you to understand and appreciate OMM as much as they do.
Boards pass rates. I really have no idea what happened to pass rates for 2022. Kinda weird, none of my instructors know what happened there. My personal theory is that when the school was forced to go online, it wasn't ready for it and didn't transition well, so that hindered learning, but again, my personal theory and I have no clue. Like I was saying above, the weakest part of the curriculum was by far and away biochem, and that is going to be much improved next year (addition by subtraction).
Sorry for the long response, feel free to DM if you have any other questions.