I basically lost interest in GPS because not riding much offroad and a bog standard sat nav suited my requirements.
As I have now made a few forays out into the wilderness once more on the KLX450 it rekindled my interest.

Basically all I wanted was something cheap and cheerful so I didn't feel I was was in the Wherthefukrwe tribe (Its a pygmy tribe in Africa that live in a tall grass area and jump up and shout "where the fuk r we" case you didn't know)

Touched on Navigator free before (mapfactor http://navigatorfree.mapfactor.com/en/ )and newer version 17 is currently out. It works on windows, android, and crappy apple. This means you can use an old phone (or your current one) or a PDA or better still an old sat nav if it runs on windows CE or similar. Most the cheapo bargain bucket chinese sat navs run windows CE, (usually found as "wince" in the menu) The PC version works fine on your laptop so you can plan routes etc easier. Tom Toms run on a form of Linux afaik so unless you can over write the OS its a no go. It supports win mobile though that most PDA works on

You can download the free nav 17 version and load the free OSM maps on for your area, OSM are user defined public maps which can be edited if you so wish to be involved. They are free and show details not normally shown on other maps as they will have been edited by joe public world wide...and yes they show the lanes and footpaths etc, hopefully some kind soul has defined the road correctly but I guess ramblers have access to so probably find some legal lanes redefined. 
Note the world wide...yes you can download any map anywhere so if you are off to darkest Peru it should be available.

Slapped it on my old £22 chinese sat nav, (this had saw me safely around France on the french trip and elsewhere in the UK so no worries), the maps and system it came with was igo8 running on windows CE 6, but this can still be used as before so you are not over writing it so it now has a choice of both systems. I installed it on the resident flash drive so no SD card (including UK map). Could not work out how to place a shortcut icon to Nav 17 but added it to favourites. You have to tell Nav17  where the GPS is installed which seemed simple enough. on the other Operating system this is probably easier or automatic for a android or windows phone you upload from an app store.

Basically for a sat nav..hook it up to the PC via cable, turn it on, win mobile on the PC might activate if it doesn't find the Windows CE or device whatever in the settings. Go to the Nav mapfactor site and follow the prompts, you want to load onto the sat nav flash drive really although you can use a SDcard, but  best to it load alongside the current sat nav on the flash drive, which might be a version of igo.
You will need to install the free maps, the setup utility is easy to use, initially it will search for paid maps but just click on the fee regions at the top and hey presto the whole world of OSM opens up.
In the nav 17 Sat nav menu you will need to turn the gps on (in the menu and can be set to turn on auto)and it should find its location on the device, mine had 3 just select any and should work.

Thats it, fire up navigator free and go test, if its not tracking you haven't configured the GPS properly.

Nav17 supports .gpx files and can log its own tracks, you can convert from kml to gpx using gps babel or similar. I have not tried it yet but I don't think it will navigate as in turn by turn instruction on a gpx route but you could add waypoints to the gpx route so that will probably work, other than that just follow the line lol.