I'm not a UCC person and am doing all in-person interviews except for 1 (due to a scheduling conflict), but for what it's worth, I was told that my impressions of sites would change significantly after visiting them in person. I've attended 3 interviews so far and this has absolutely been the case on all ends of the spectrum (i.e., reallyyyyyy NOT feeling a site to being pleasantly surprised by how much I enjoyed another that was just kinda "meh" on paper). So I might follow the recommendation of
@eventualphd and prioritize your sites by how much you like them on paper, and then see if attending those (maybe your top 3 or so?) would be feasible. Traveling is absolutely hectic (not to mention expensive AF) especially in the context of all the other demands we have as grad students. AND, you're going to match at a place for a year, so wouldn't it be great to try to get a feel for the site and the city if you can? Whatever you decide, good luck! And Happy Holidays