Why don't routes on my GPS resmble BaseCamp routes?

Generally when you're having problems like this, it comes down to the maps or settings. You're sure that the maps you bought are "routable" (it will say something like "supports turn-by-turn directions")? Not all US TOPO maps are routable (the 24k are, the 100k are not), so something similar might be going on with the UK maps. Are you sure you got those maps onto the device? Using one map to plot the route in BaseCamp and another map on the device also causes problems. Since you say it's working in BaseCamp, the maps sound like they're routable, but the behavior of your eTrex makes it sound like something is wrong there. Sounds like it's just drawing straight lines between waypoints, so you may have to get the eTrex to recalculate the route somehow, maybe by telling it to follow the route. Check the settings on your eTrex and in BaseCamp and make sure neither one is set to "direct" routing. A route is just an ordered collection of waypoints, so the way it works is that BaseCamp will compute a route using its settings based on the map connecting all of the waypoints in order, and your device will independently compute a route for the same waypoints based on its maps and settings, so they may not agree. You need to make sure that all of the settings and the maps are the same.

Thanks Schinder. I opened the Routing page in my device settings and changed the Lock to Road setting from No to Yes and that did the trick. Thank you for steering me in that direction.

Glad it's working but Lock to road isn't what did it. Lock to road simply means that when your GPS works out its location it will correct it so that it's on the nearest road. You must have altered something else.

Either you didn't give your Etrex enough time when you first looked, as Basecamp doesn't send a route but a collection of points, which your GPS turns into a route or you changed the routing setting on your Etrex from Off road to On road.

I'm not sure about the Etrex, but the Edge units require "track" files (not "route" files).

I'm assuming you have a "route" in Basecamp. Try converting that to a "track" and then sending the file to your unit.

If you Double click on the course in Basecamp, you'll get a list of points.

The track/route convert button is at the bottom of that screen.

It could also be due to a setting on the Etrex.

The Etrex range will take a route as well as a track, so that's not the issue. I agree its likely to be a GPS setting, as they can be set to navigate on or off road. Setting to off road will get straight lines between points, as would setting to on road if no routeable map is selected.

I'm not sure about the Etrex, but the Edge units require "track" files (not "route" files).

Possibly some of them, but certainly not the 800. I send routes to mine all of the time, and they work fine. There used to be a distinction between a course and route on the earlier Edges (my 705), but that's disappeared into a simple check box on the Edge.

You have to send tracks to an Epix, but that's a bug in BaseCamp. The Epix is fully capable of doing turn-by-turn, but BaseCamp doesn't know it (and is never likely to learn, since Garmin has abandoned the Epix). You have to send tracks to the various Fenixes, but they don't (officially in the case of the 1 and 2) support maps or turn by turn.

I'm not sure about the Etrex, but the Edge units require "track" files (not "route" files).

I'm assuming you have a "route" in Basecamp. Try converting that to a "track" and then sending the file to your unit.

If you Double click on the course in Basecamp, you'll get a list of points.

The track/route convert button is at the bottom of that screen.

It could also be due to a setting on the Etrex.

I am using routes, but it turned out to be the Guidance Method setting that was causing the problem. Once I changed it to On Road for Distance the routes started looking like what I expected. Thanks everyone!