eTrex 20x and Maps

( Background - I've intermittently had interest in handheld GPS . In the woods for hiking, hunting, 4x4ing, occasional geochaching. I am Luddite with computer related stuff , but fluent with map & compass . Previously used GPS simply for my actual Lat Long , while using map to interpret where I was, and where to head .

22yo daughter about to recieve already purchased eTrex 10. I am probably about to recieve eTrex 20x for Fathers Day .)

One of the online vendors offers a bundle of the 20 together with a 24k card for one Region. Great , until I looked into it , and I live close to the border between two Regions .

Called Garmin , with pre-loaded cards , I would have to switch cards . I could download both, and load onto a microSD , but my eyes are glazing with all that computer guy talk.

Also mentioned was the nationwide 100k ( 1:100,000) .

Looked thru Garmin website some more, also saw the "rasted" .Image of paper maps is ok with me , I'm a paper map guy from way back. But it says its an annual subscription, what's that mean ? It says in description that whatever is in the GPS will continue to work .

USGS meaningful revisions are decades apart, so being out of date is minor concern . Does the whole country load into GPS upon payment, or only those quadrangles I physically travel thru ?