Of all our Garmins, my favorite is old yeller.
The interface is a serial connection (which easily becomes USB with an adapter). Here's a link to the part from Garmin:
http://shop.garmin.com/accessory.jsp?sku=010%2D10206%2D00
I use GSAK to transfer waypoints: http://gsak.net/
If I'm not mistaken, the eTrex can store up to 500.
As for using it... it really isn't so difficult. Try downloading a manual from Garmin:
http://www.garmin.com/products/manual.jsp?...ct=010-00190-00
Why it's not so bad:
1) Batteries last almost forever
2) It's nearly indestructable (thus great for handing to the wee Waddies)
3) While the non-mapping features make it difficult to use only it to get to a cache area, once there, it often has the best range and doesn't seem as put off by large buildings, tree cover, etc. as some of our more expensive equipment.
Sorry, can't answer your question about retrofitting antennas. Maybe someone else can speak to that.
