I haven't been inside having always used the drive-thru. There isn't a smooth entrance from the road and you could probably mess up your suspension if you hit it hard. It's a sharp turn up to the drive-thru speaker, so I'm always a little further from the speaker than I'd like.
Having gone through these trifles, but keen observations, the service is good and the burgers are great. Well worth the trouble of navigating this weird, old lot.