I love geocaching! I started doing it about 5 years ago and have done it a lot, in many different places---around home, on day trips, on vacation in many states, in big cities and very remote areas!
With my experience --- for a beginner I would recommend things like the following:
-GPS- of course
-extra battteries for the GPS ( you always want to carry some!)
-a couple pens- ballpoint ( or one of those write-anywhere type pens)
-a couple of pencils--- I would cut these in half and resharpen so they aren't so long (sometimes if the log in a cache is -damp a pen won't write on the paper)
-some bug spray- one large for the car, one small ( or those wipes) for the backpack)
-a small first aid kit- with band aids mostly
-a couple bandanas- these have come in handy man times!
-a disposable camara- never know what wonders you will see - and fun to take pics of different caches , or travel bug travels
-lip balm
- I always had a few sandwich sized ziplocs bags in my bag- to replace a bag that is torn in a cache etc.. and they have come in handy for other random things and don't take up much space
- some plastic grocery bags(many people keep them in a film canister) - geocachers have a thing called "cache in, trash out"- meaning pick up trash on your way out of a park - do your little share of beautiying the area etc..
- a small notebook for recording notes ( about the cache, if it was damaged, cool things you saw, what you took and what you left etc...)
## you could purchase a set of travel bug tags for him to start a bug from the
http://www.geocaching.com website- they aren't that expensive
## you could put a coupon in there to purchase some "signature" wooden tokens when he decides what his geoaching name will be ( you can get custom ones( they will send you samples too I think) here
http://www.wooden-nickel.net/ )
## or a coupon to have a "signature" rubber stamp ( self inking kind) made when he decides his geocaching name ( I would sign my name then had a little mini image stamp I found that matches my geocaching name that I always stamp next to my log in the cache
##There is a few books out there on geocaching-- Geocaching for Dummies is one of them. I have not personally read any of them so I can't give you a recommendation
## a bag of some sort (I have a "geocaching" backpack in my car , then inside that bag I have a smaller bag - the size of a paper back novel that f most of my stuff fits in . Most caches I take my small bag ( some people use a fanny pack )- I only take my backpack on long hike type caches when I need water and the big bug spray and a "snack" etc... )
## some good but lightweight hiking shoes/boots??? depends on what kind of caching he might be doing
All that being said - I know several people who cache , taking nothing with them but the GPS!
I will probably think of something else later but...
Hope that helps! Great idea, hope he likes it! Beware though- it can be addicting!
pixiestick