I've got to wonder why some of these smaller arenas don't more regularly bid for regionals. Speaking solely from the east, every school in the east with the exceptions of Princeton, Maine, and the North Country have relatively easy access to I-90. The East Regional should not stray far from I-90 and the Northeast Regional shouldn't stray far from the Boston/Metro area. Maine and the North Country are used to traveling to get to civilization and Princeton, well, it's Princeton.
Albany basically hosts the East Regional every other year but they've had a hard time getting a host for the other years. Albany is a huge AHL arena and even with the upper bowl closed, just about any regional will look like a ghost town. Having Yale, QU, and RIT all in that regional and even Lowell within shouting distance was a big win but the numbers weren't great for that arena. However, the smaller arenas just don't seem to be into the regionals. Glens Falls would have sold out. Syracuse would have had a full look (assuming they don't swap the whole regional and send QU to Worcester because of distance). Bridgeport or Springfield would have been a near sellout, especially with the combatants.
The desire for the NCAA East regional is so slim that, for some reason, the East basically lost its regional next year to have two Northeast regionals. A 5,000 ticket sale weekend with the high end being a sellout should be desirable to most of these smaller arenas and if Albany can do it, there's no reason some of these smaller arenas can't.
The problem I have with campus sites is accessibility and space, even for the home team's fans. Many of the ECAC arenas and all of the AHA arenas with the exception of Army and possibly RIT (haven't seen their arena) could not accommodate a 4 team regional with press requirements, locker room space, etc. etc. If you put a 4 team regional in Appleton, for example, they'd probably have to commandeer seating areas for press, making it an even smaller arena. Even Clarkson and its newer arena doesn't have the accommodations for 4 Division 1 hockey teams and all they bring. Sure, they can host junior hockey tournaments with a number of teams but that's different than hosting a 4 team NCAA Regional.