Using a GPS for navigation is not a subject dear to the hearts of all sections of the cycling community, objections along the lines of "well you really shouldn't rely on it" and "it will never replace a map and a compass" are common.
Whilst both of these statements may be a matter of fact, neither of them (nor any other I have heard) precludes a GPS from being an exceptionally useful tool. One which I would not like to be without when touring or on an Audax.
These days there are a plethora of GPS units to choose from but, in my opinion, there aren't many that compare with the Garmin GPSMap 60CS from a cycle touring perspective (except perhaps its replacement the 60CSx)
Whilst the 60CS may not be at the leading edge of GPS design any more (not necessarily a bad thing) it has a colour screen, enough memory to store street level maps for the whole Scandinavia trip, 20 stored trip logs, an altimeter and, perhaps most important of all, it will run for 10 to 15 hours on a pair of AA batteries (rather than an in-built rechargeable).
Not only do you get to know exactly where you are and where you want to go but, when you get home, you can download every statistic you could want about your trip, as well as the route profile, onto your computer.
For the best battery life from the 60CS I would seriously recommend using rechargeable NiMH 2500 mAH batteries rather than Alkaline type batteries. I have tried loads of makes of Alkaline batteries with the 60CS and never got more than 7 hours use out any of them and the average was more like 5 hours!
I regularly get more than 15 hours use from a pair of NiMH batteries. I carry four with me and use each pair in rotation, discharging as fully as possible (using a small torch) before recharging. You can get a pack of four NiMH rechargeable batteries for about the same cost as a pack of four Alkaline batteries so its a bit of a 'no brainer' really.
Note: Those touring on carbon forks and thinner, higher pressure, tyres the smaller Garmin Vista HCx might be a better bet, as severe vibration on the handlebar mount has been known to cause intermittent power cut-outs in the heavier 60CS range.