Is it possible to get the tix at the box office a few days prior to the show to avoid the $ convenience fee?

I think they have a web site that handles sales, but I haven't used it.

You can call to see if they are there. But they don't have a box office that is regularly open unless a show is happening.

If an event has an event page with link to ticket site, mostly likely way to get the tickets. Their website usually has links to aforementioned.