How far to the farm?

Okay, this might seem like a bit of a random question, but how far do you think it is from the mall to the farm? I mean that as in how long would it take for them to walk to and from? What would you consider to be a believable timeframe if, for example, someone walked from the mall to the farm to get someone and take them back to the mall with them? How much time could have passed between them leaving and returning, without making a very long stop at the farm (no more than 10-20 minutes)?
It's been a while since I've seen any episodes where the farm was a part of it, and I can't remember enough to make up my mind. Did they ever say anything about how long it took to get there? I don't remember anything like that, but then with my memory I probably wouldn't. XD Since Dal worked there and came back to the mall most nights, it can't have been too long a walk, but would it be over an hour to walk to the farm? Over two hours? I doubt it could be more than that, as it seemed like they constantly were going back and forth from the farm in s2. Personally I would say it would go between 2 and 3 hours before returning to the mall. But what do you all think?
I'm asking because I'm working on a fic, and I really want to get the timeframe right. There's a lot going on at once, and right now I can't get it organized right in my head to make it fit together, and I realised that this is exactly the kind of situation I wanted a community like this for, so I figured I'd ask for a little help. :)