I may sound like a dunce, but humor me; can I buy tickets at door?

You can but it depends on the show

For most shows, yes. However, I would inquire with Orpheum in case.

I have in the past.

I believe so. You can ask them on facebook because they dont answer the phone

It depends on the venue or who is performing but you can call the Orpheum and ask them. I have played there before and I sold tickets at the door.

More than likely

Usually