Hi - I am asking advice on behalf of a friend. 
They have a 12 month old rescue who keeps running away when they let her off the lead.   She knows where home is and turns up 20 minutes or so later!
She goes to work with Mr and allowed to roam around his yard with open access to about 60 acres I think.  They don't like tying her up, but apart from leaving her home alone or crating her, I don't know what else to suggest. 
I have given some advice but other ideas would be appreciated.  I have suggested that they go back to basic training and not let her off her lead for a week and then find a nice enclosed area and start training over again. 
They also seem very reluctant to treat her when she does return to them - if it works why not do it?  She is also due in season at any time, so they need to get some form of control over her or the inevitable may happen! 
I don't let my dogs run off until I'm confident they will return to me and it does make a difference having more than one.  I personally have never taken on a rescue before and wondered how others have coped and are in a better position to advise.  One thing they were advised to do was change her name - which they have done and that has helped to a point.
Your thoughts and ideas would be much appreciated.

Why arent they willing to gove her treats for coming back? Seems very odd to be reluctunt to do it, but her favourite toy could also be used.

What you said is best by going back to basics, good way to do it is to teach recall in the back garden and on long lead outside on fields and walks (as she is so proned to run off, she shouldnt be let off again until they know she will come back, with her season coming up thats a 100% must!!)
When she has a good recall you can go somewhere isolated and let her off for a small run and then put her back on so she gets used to being on and off lead and then after a while she should start to understand

I don't understand why they are reluctant to give her treats - possibly because their previous dogs didn't need them.  I think it's a positive way to start and the tastier the better!
Glad you agree about going back to basics - they may have to just keep going over the same things over and over until she grasps it - or probably 'wants' to do it!

Would encourage them to use a long line especially if she's a "runner" and is coming into season. Ask them if they want a litter of puppies in a few months time etc and see if that persuades them to keep her on a lead.

One of the first indications that mine is coming into season is that her recall, which is usually solid, goes to pot   that is when I start keeping her on the lead.   It would be foolhardy to say the least to allow an in-season bitch off lead   unfair on other dog owners and downright dangerous if she decided to run off and got into traffic or mated by a much larger breed.

Really if she has no reliable recall they need to treat her like a puppy and take her right back to basics, find what her 'switch' is, whether its mega lovely treats or play/toys, and practise regularly around the house/garden and only when she's totally reliable there graduate to other safe situations.  This will take time, effort and patience.   They may need to join a training class if they are having problems doing this on their own
To be honest, from  what I've read in your post I'm wondering whether they are willing to put in the time and work to achieve a safe recall, I'm hoping I read it wrong

> Ask them if they want a litter of puppies in a few months time etc and see if that persuades them to keep her on a lead

worryingly as we know many people foolishly think they do want a litter...

i'm surprised she's not been spayed if shes a rescue, i thought most rescues have that as a requirement?

I think in my own mind they are having second thoughts. 
It is quite different taking on an older puppy rather than one at 8 weeks. 
If this were mine, the first time it didn't return, it would be back on a lead until I had worked hard on the recall and I felt they were going to be more responsive. 
She is very food orientated - for which I would be very grateful for - but they don't seem to like it - can't really find the reason why.  Possibly because their previous dogs always wanted to return to them.
It is going to take a lot of hard work and patience to sort her out, but she's a lovely girl and I hope they can work through it.
I especially hope they take notice about what I've suggested to them about not letting her off the lead from now until she has at least well passed her season.

You don't say how long they've had her, but if it's a matter of weeks or a couple of months then she will not have the habit of returning to them   she may not even have bonded with them properly yet so why should she return?  If she had no previous training or even had to fend for herself then she will take time to learn recall.   You don't mention what breed or mix she is (if known) but some breeds are very independent minded and take longer to learn the recall (and also need more motivational aids/treats)   This means that they have even longer to practice and with lots of work can improve greatly

They've had her for just over 2 months now I think.  She did have training previously - but not sure of this did involve much recall work.  She is a GR - which are usually very easy to train.  I think they can make lots of improvement if they are prepared to make the commitment - I don't think they realised quite how much work a rescue dog may need.  I help where I can, but it's down to them to put in the work on a daily basis really.

To be honest, if I were left to roam a back yard with access to 60 acres and my master was working, I'd be off as well.

What interest does the dog have to stay? I'd be off exploring and getting up to mischief.

It does not take a scientist to work out that a dog needs to be secure in any garden, yard or work place, most will go for a wander especially if a pup with a whole world of scents and excitement out there to explore. It is not really anything to do with recall, just the poor thing being left in a vastly open area like that, she needs entertainment and stimulation from her onwer.

So he either pays out for a large dog run for the dog whilst at work, (that would be my preference) for her to be safe and secure, or he keeps her inside a locked room and then takes her for a nice walk a few times a day, or he just does not take her at all and gets a dog walker for home.

When she is a fully mature dog, and has been used to going to work with him and has built up a good bond with her new owners, she most probably will not be inclined to disappear, but right now he is playing with fire.

I would suggest the large dog run.