New C-17 co-pilots travel a crazy amount. Like 200+ days per year in some cases, depending on the base. I have friends that were flying the Kabul evac mission within months of finishing initial qualification, and even the ones that didn't have already been to 20+ different countries. My old ROTC detachment commander flew C-17s, and has been to 90+ countries. If you like making money, traveling, and don't have a family, C-17s are a sweet deal.
C-5s and tankers have a bit more stable lifestyle. Tankers still travel, but stops are pretty routine and we go where the receivers need us, whether that's fighters over CENTCOM or reconnaissance over PACOM. C-5s obviously are limited by runway length, so don't expect to go anywhere super remote, but there's a running joke that C-5s only seem to break in the nice places, "stranding" crews in Hawaii for a few weeks. KC-46s, and the KC-10s that are still around, live the Gucci life, with decent bases and a pretty straightforward mission of refueling and cargo transport. KC-135s are more broken down, and get some unusual taskings and missions based on our capabilities. With that being said, I love the 135 and wouldn't wanna fly anything else because of the sheer variety of what we get to do.
C-130s we like to joke are pretty much in the Army at this point. Lots of sleeping in tents, landing at remote airfields on night vision goggles, etc. Still get some nice trips, especially the Yokota and Ramstein folks, but they're a lot more "tactical" than the other airframes, even the C-17, which has some tactical airlift capability. Also, C-130s sometimes get shot at on the airdrop mission. It's rare, but that just goes to show how close they can get to the action.
Also, since I was in the same position a few years ago, it's good to gather info on the opportunities out there, but don't sweat it too much. By the time I actually got to drop night and had the chance to make my dream sheet, it was a super easy decision to make and in many cases the decision is made for you. Worry about getting into a commissioning source, getting a pilot slot, and finishing UPT.