i have the garmin eTrex H and love it but anyway. the idea of the gps is to just get you in the general area,then its up to you and your geosense to find the cache.
yea you need to right down the number in the coin or travelbug to be able to log it. The info on the cache page is a reference number only. you could try emailing the owner and ask them for the number or just not worry about it this time.
i used a tom-tom for a couple of caches in the begining and hated it. i would recomend the Garmin eTrex H. its good, its cheap, it gets the job done, its yellow.
it dosent take too very long. i had one that i submitted one night and by the time i woke up the next morning it had been published with 2 finds already.
i have the garmin etrex h and it gets me to all the caches just fine. you can get a ne one for 89 dolalrs at wal-mart i ordered the serial cable off ebay for $10 and it sends the waypoints to the gps so i never have to do anything except change the name of the waypoint so i can identify it on the go.
I use the serial port with my garmin and it works just fine. what i did is i went to the garmin website and got the drivers and installed the updates and it works just fine. My roomates garmin is a little tricker with his i have to keep hitting look for device until it shows up.
another question is are turning your garmin on when you plug it in?
i just started geocaching not too long ago and i don't have a gps. i ordered one last night and it arives next monday. but so far i have found 8 caches without a gps. i know that i wouldn't have so many no finds if i had the gps but it is possible to do.