The main thing i do with both my n800 and my n810 is geocaching. These 2 devices have lead me to over 500 find in 5 states. For a first timer i would suggest going for ones that are 1/1 or maybe 2/2 max (terrain rating / hide difficluty). And if you are going to bring kids try to do some of the larger caches because kids love the idea of trade items (where you trade something you have for something in the cache).

Now to your Questions.

I use anywhere from level 9 to about level 5-6 to drive around looking for caches. Level 9 is for when you are driving around on highways and Intersates. The lower the level the slower you need to be driving to prevent overshooting.

For your first time having GPX files would be great but don't go off and pay 30 bucks for one weekend. If you and/or your family becomes addicted the 30 buck is worth the money just because of the time it saves you. If you PM me with the zip code of where you are staying i will happily make you a GPX file for your trip.

The GPS on my N810 built in gps is good enough for your first shot at The Game. Watch out of heave tree cover and tall pine tree because they will kill your gps signal. I like using the bluetooth puck that came with the navacore system to prevent power drain from the N810. If your n810 starts saying low battery turn around ,walk out and charge it (its not worth getting stuck somewhere). the N810 does not have the longlife that the n800 has on low power.

Step by Step.
1. install GPXview and Maemo Mapper
2. download caches in ether GPX or LOC format to your N810. (GPX is better because it has all the info in it from the cache page.) Make sure it is in an easy to find to folder.
3. Lanch GPXview
4. Add you downloaded files to GPXview by
- menu
- import
- File/folder (File for something like a Pocket que (GPX) with 500 caches and folder if you have a lot of individual LOC/GPX files)
- Select what file/folder to import and wait
5. Select and open file/folder
6. Export to maemo mapper
- menu
- export
- Meamo Mapper POI
7. Find and select the nearest small, full sized or large cache (best size for first timers) with a max of a 2/2 rating. Use the Maemo mapper symbol in the Goto tab of GPXview to center maemo mapper on that cache.
8. Switch to Maemo Mapper to drive to withing a reasonable walking distance of a cache (no more then 100-200 yards with small kids). Use the compass in the goto TAB of GPXview to get from your parking spot to the cache. If you are looking for a larger cache, like an ammo can, you should see it or its hiding spot from about 10-50 feet.

Things to remember while Geocaching.
1. start slow. This is going to take some time to get good at it.
2. Keep safe. No cache is worth an injury (Not even a First To Find)
3. Have Fun. This is just a game. The fun is in seeing out of the way places and things while hunting small treasure chests full of cheap toys.
4. Protect the cache. Don't cause someone that does not know about geocaching to find the hide. Most of the low rating ones will not require spy like stealth.

Have fun on your first GPS vacation. May all your adventure be grand and full of fun and treasures.

If you need more help massage me here or 'bigscot' on geocaching.com