THE risk/reward equation is a useful way to work out things.

You weigh up the cost/benefit, and then, regardless of common sense, you go for it.

That's the thinking we applied recently when relocating a campervan from Cairns to Sydney - a distance of some 30 gazillion kilometres.

We figured the risk if we didn't drive back was that we'd never get to know just how big this country is and how numb a bum could get.

The reward was we got to kid ourselves we saved money on accommodation while spending cash on petrol, two-minute noodles and bum-relieving beverages.

We'd been up in North Queensland to visit our daughter who has moved up there to study. We'd applied risk/reward thinking to that too.

The risk was she'd set aside at least five minutes aside to enjoy our company. But we correctly calculated that may be stretching it, parents being inconvenient and all, unless they take you out for dinner.

So we flew up under the crafty guise of doing something for our wedding anniversary and stayed in four-star hotels for a week to ease our pain, without her.

The risk if we didn't do that was we'd never understand how expensive it was going to be visiting our daughter in North Queensland over the next six years, unless we won Lotto.

The reward was we became accustomed, mentally and physically, to king-size beds, humidity-defying airconditioning and buffet breakfasts.

To counteract that, we drove back, in a campervan complete with a dodgy rear vision mirror that eventually fell off near Port Macquarie, and no cutlery.

Now, if such romance appeals, you can either get your B-double licence, or visit websites that advertise campervans and cars that rental companies need relocating.

Typically they'll list the types of vehicles available and a window of time in which they want the thing moved. Usually you get free rental, or free petrol or free insurance or sometimes all of the above.

To our dismay, the cruise ship Rhapsody Of The Seas, berthed at Cairns the same time we were up there, was not on the list.

We instead secured a four-berth camper van that not only needed to be returned from Cairns to Sydney in eight days, but could have done with a lick of Glen 20.

Five of those eight days were spent driving and in retrospect we probably could have done it quicker swimming, if only you could swim in North Queensland without being killed by stingers or crocs.

Of course, if we had swum we'd have risked depriving ourselves the chance to do what every grey nomad and backpacker does, and that's free camp.

Free camping is where you pull up by the side of road and camp, not unlike a homeless person, for free.

Grey nomads have been doing it for years and counter-act the perception they are homeless by dragging caravans the size of their actual homes behind them.

Or at least caravans that cost as much as their actual homes, somewhat negating the concept of "free-ness". It is amazing the scale out there on the road. Or at least beside it.

Queensland is quite tolerant of free camping, unlike NSW, which will set up a petition the minute you pull up to run you out of town.

Ideally you want at least drinking water and showers in your free camp site, and not too many Ivan Milats. A hotel nearby is a bonus.

There is a network of sites around Australia which travellers can tap into.

If you have any trouble, check with family members who have retired recently. Chances are they'll have gone Bedouin and know lots of good spots.

But my advice would be to not wait until you retire because free camping frees your mind and the sooner you do that the better.

Free camping provides opportunities to set up at sunset and contemplate the difference between sleeping next to a swamp as opposed to a wetland. Answer: None.

It provides the opportunity to contemplate whether you brought any insect repellent. Answer: Hopefully.

And it provides the opportunity to contemplate how memorial parks in small country towns are not only where people "up on their luck" sleep for the night, but also people down on their luck.

Now this type of mobile adventure may sound unrewarding to some but the risks of hard work in modern campervans aren't much once you work out which switches flatten the battery and which don't.

Living on the edge, like hard work, is reward in itself, particularly when it's the edge of a mattress which used to be the back seat of your van.

It's true, driving long distances can be a little mind, and bum, numbing. But if you didn't give it a try you'd risk not getting to wave to people driving campervans from the same rental company in the opposite direction. Most survive the distraction.

You'd also risk not listening to so many previously unheard of Queensland country radio stations. I now understand why Maroons supporters are so parochial and also why so many Queensland country radio stations are best left unheard.

All in all, I found the experience rewarding, and an offer to do it all again tomorrow would be music to my ears, no risk about that.