I'm looking at getting the garmin inland lakes and waterways maps .... I'll be doing a bunch of backwater canoeing and portaging in the adirondack mts of upstate ny. I was wondering just what kind of resolution these maps had. can anyone that has this go and look to see if the fulton chain of lakes up to the saranac lakes had any detail? I'm also torn between getting the preloaded data card or getting the blank card and dvd. can the dvd be viewed on the computer? this there better method? topos maybe? and (some of) those are free. but I'd still need to get a data card ....... I've seen 64, 128, is 512 the biggest? btw, I got a 478 .... and from what I understand I can't use the "vision" version of the maps.