All maps available on pastures, so just copy to SD card.
Talking about Garmin handhelds with cartography support.
I have Oregon 450 but screen seems too small to me.
Cheaper device to me some Android phone. Have Alcatel OT-990 in action-bundle 35,00€ and bigger screen visible well in sun.
Loaded Orux maps app on it, 1:25000 cartography (topo maps Slovenia excellently calibrated in Ozi format) got from Partis-u and converted with OruxMapsDesktop to format app reads.
Map on screen same as paper one.
Tested thing in field too, GPS very accurate, pulled track cc. 10 hrs about that much battery lasted without SIM.
Orux maps program has also statistics more extensive than Garmin.
My experiences once you have these toys use them some time, later very useful only where you don't know where forward or back anymore!