Like ALWAYS, when I post a question to the Forums or the Answer hub, I figured out the solution immediately after posting:
There are a couple Boolean Variables associated with the Loaded Map Instance, one is Should Be Loaded, setting this to false seems to unload the level. I’m not sure if it actually does, because I can set the Boolean back to True and the level reappears. My test levels are pretty small so I can’t really tell if it’s unloading everything correctly.