Ha, i was just reading up on the zen of z... i think that is the best route as well... so you are saying the order of occurence would dictate which layer is on top? Very cool.
There is actually a compnay out there marketing a GPSR device that you wear while skiing to calculate one's total vertical for a day.
i do think a WAP or possibly a basemap that would be compatible with Garmins would be a nice thing to have, but if you are that hip with your GPS than you should be able to figure out where you are anyways

thanks for the input... i guess i could make this a pretty easy project and leave out the db all together and just use a simple form, that would be too easy tho!