Garmin devices allow custom waypoints and routes to be created and used. Using Garmin’s MapSource software(free software from Garmin), waypoints can be transferred to your Garmin GPS.
Kenya and the rest of east africa are ever changing and Garmin are never able to collected all data, if you gather waypoint data on your travel, this data can easily be transferred to your hand held mapping GPS such the Garmin Etrex and Garmin GPSMAP 60.
Instructions
1. Connect your Garmin device to the computer using a USB cable. Power on the device, and set the Data Transfer mode to “Garmin.” This may not be necessary with some Garmin devices.
2. Download and install MapSource (see Resources for a link), then run the software. Create a waypoint by clicking on the “Flag” icon, or “Tools,” then “Waypoint.” Click on the area of the map you wish to use as your waypoint. Change the details that appear, if desired, then click “OK” to save it.
3. Click “Transfer” and “Send to Device.” If the name of your Garmin device does not appear automatically, click “Find Device.”
4. Click the “Waypoint” box under “What to Send,” and choose all of the waypoints you want to install on the device. Click “Send” and “Turn Off GPS After Transfer.” The waypoints are downloaded to the device.
If this doesn’t help, check out this forum thread with detailed text and screen shots on how to do it. Waypoint Installation Guide.