Garmin GPS Questions

As my old GPs had finally died, I am looking for a mulitpurpose GPS for turn by turn, off road and boating. The Garmin Nuvi 500 seems to be the closest to what I require as it is turn by turn, can take the marine charts and is also waterproof - a requirement that I must have..

My 1st question is can Tracks 4 Australia and Shonky maps be loaded onto the Garmin Nuvi 500. I have used these on my old GPS and they have been very useful.

Also my old GPS was a Garmin eTrek Vista and I have heaps of tracks (mainly places I have been in the boat) saved on my PC and want to use these on the new GPS. Can they be downloaded via Mapsource which I also own.

Stevesub