On my eTrex Vista HCx I can set "bicycle" for the routing option and it'll try to avoid major highways wherever possible. This can also result in some odd routing decisions, e.g. in the middle of nowhere, going along a perfectly nice backroad which the GPS considers a highway, it wanted to get me off into this network of dirt tracks (which it obviously didn't know were unpaved). But all the same, the routing feature is useful in so many situations that I am willing to put up with the occasional quirk.

I've actually never done this. What I did was to load the entire City Navigator for North America onto my 2GB card. I haven't used the PC software since then - if I need routing, then I just ask the GPS to do it. This is partly because I just use Linux these days as my desktop, and can't be bothered farting around with firing up the Windows virtual machine.

What I did on my last tour was that I had paper map printouts (a very knowledgeable user on crazyguyonabike kindly plotted out a good route from St Louis to the Pacific, and I printed these out on normal paper with the route highlighted in yellow). Then I had the GPS on all day, usually not in routing mode but rather just to record trackpoints for later uploading to a google map on my journal, to show exactly where I went that day. I only used the GPS routing if I needed to go off-route to find a motel, shop, camping etc. Then if I needed to get a route, I would put in the nearest point which I could discern on my paper map (e.g. a road out of town, or the next little town on my route, if there was obviously just the one road going there then there wasn't much chance to lead me on any weird routes). This would usually get me back on track, and I was able to navigate strange towns with ease.

When using the routing, it was a question of looking ahead to check to see where the GPS wanted to take me, and then making common sense decisions to ignore its advice when it was obvious I was being taken the long way around. The GPS recalculates so quickly that it's actually quite fun to watch it realize I missed its recommended turn, and it frantically recalculates a new route to shepherd me back to its route. I actually have gotten very attached this little GPS! It's like a faithful companion who's always keen to help and tell you how to get to where you want to go. In the middle of nowhere, all alone, you still have a friend. Maybe I need psychiatric help.

See above - planning the route on paper printouts gives you the big overview, and also a backup in case the GPS stops working for some reason. So you can follow the paper map most of the time, but the GPS is there for short routing help - usually across towns. Or, if you come to a strange junction that isn't shown on the map etc.

Bicycle mode should take care of this - unless the map data you're using doesn't have information about what types of roads these are. That's a possibility - the GPS can only make decisions as good as the data it's working with. City Navigator usually has a pretty good idea of what is a highway.

This is a very interesting question, and I'd like to experiment with it myself! I have City Navigator, but I'd like to try the free alternatives.

Thanks for that link - I wasn't aware that they had progressed so far with the free maps, to the point where they could cover the whole country. I wonder how comprehensive it is. The whole of North America for City Navigator fits on a 2GB card, so I wonder what additional data this file has that it takes up 4GB? That's twice as large! Actually City Navigator doesn't even use up the whole 2GB, I have a good 400MB left over for storing my trackpoints. Does the free map have a POI (Points of Interest) database?

Thanks!

Neil