Can I read /var/mail with a GUI?

I can set up local-only mail accounts using sendmail or postfix, and messages will be stored in /var/mail/USERNAME and readable in a terminal window using mutt. I tried setting up a couple of MUA GUIs to read from this mailbox, but they all expect SMTP or IMAP details. (Tried Evolution, Geary and Thunderbird.) Is there any way to access a local mailbox with a GUI, without having to configure a local SMTP or IMAP server? I don't mind using a dedicated GUI.