In the flash-sideways, Locke lies about what he was doing in Australia multiple times. He tells Boone he went on a walkabout. He tells Helen and Randy Nations that he went to a conference until that story falls apart.

LOCKE: Actually, I went on a walkabout.
BOONE: Really? Like--like Crocodile Dundee?
LOCKE: No, not exactly. But--but, uh, it was pretty intense. We--we spent ten days in the Outback and, uh, nothing but our packs and our knives. We slept under the stars and made our own fires, hunted our own food.
BOONE: Wow. I wouldn't make it two days without my cell phone.
BOONE: You're not pulling my leg, are ya?
LOCKE: Why would I pull your leg?
~"LA X" by Carlton Cuse & Damon Lindelof


~~~
HELEN: So? How was the conference?
JOHN: Boring.

RANDY: Welcome back, Colonel. Wow. You got a nice tan in Australia. Did you miss us?
JOHN: Sure I did, Randy.
RANDY: So? How was the conference, John?
JOHN: It was okay. I didn't really learn anything.
RANDY: No?
JOHN: But um... I made some good contacts, though.
RANDY: Really? That's interesting. See uh... Ken Fisher called and said you had to cancel your lunch with him.
JOHN: Right, right... I was a little under the weather that day. Probably jet lag.
RANDY: Really? 'Cause then the seminar people called and said you hadn't picked up your credentials. I did some checking... and it seems you didn't attend a single event. Since we sent you to Sydney on the company's dime... where the hell were you?
JOHN: Look, Randy... I'm really sorry. Why don't we just call it my vacation week?
RANDY: I thought you wanted that vacation week in October. You know, for your wedding.
JOHN: Please, Randy... look, I know I shouldn't have lied. But where I was... it's personal. And I... and I really don't want to talk about it

LOCKE: I lied to Randy, I didn't go to the conferences in Sydney.
HELEN: What?
LOCKE: Open the case, Helen.
HELEN: What are these for?
LOCKE: My walkabout.
HELEN: Your, your what?
LOCKE: My walkabout. An adventure in the outback. Man against nature. But they wouldn't let me go. And I sat there yelling at them. Shouting at them that they couldn't tell me what I can't do. But they were right. I'm sick of imagining of what my life could be out of this chair, Helen. What it would be like to walk down the isle with you because its not gonna happen. So if you need me to see more doctors, have more consults, if you need me to get out of this chair, I don't blame you. But I don't want you to spend your life waiting for a miracle because there is no such thing.
HELEN: There are miracles, John. And the only thing I was ever waiting for was you.

~The Substitute by Elizabeth Sarnoff & Melinda Hsu Taylor

~~~

Keep in mind Locke lies throughout this episode, as does island Locke. Is it possible that Locke's last story to Helen was just another story? Could he have been doing something else in Australia? Something related to the Shephard line or the Island conspiracy that appears to stretch beyond the scope of the Island?

Edit to add: I realize he could have just been sightseeing, but if the "Walkabout" fell through he could have gone to the conference.

I realize he could have just been sightseeing, but if the "Walkabout" fell through he could have gone to the conference.

Agreed. If your secret plan didnt work out, just go to the conference so you dont lose your job. Its possible he could have been doing something else or meeting with someone.

He could have been going to see the healer because he wanted to walk down the aisle with Helen...

He could have been going to see the healer because he wanted to walk down the aisle with Helen...

I didn't even think of that! I keep thinking about Australia, how Hurley thought it was the key...

I didn't even think of that! I keep thinking about Australia, how Hurley thought it was the key...

good thinking, and that could be something he wouldn't want everyone to know about as well..