I use an anachronistic Garmin GPSV.  Seems like most GPS applications don't
require constant attention so an inexpensive PC with a serial port and
600x800 resolution would provide just the magnification you seek.  A 12v
power supply and W98 is all you need for Garmin software.  A 166Mhz 64MB 5GB
HDD is plenty for the dedicated application.  Add sound (Garmin has this
feature in it's software) and the anachronistic electro-nag will tell you
where to go.  And even announce the turns as you go.  So will MS Streets and
trips in later versions.  Most of the MS products that are new no longer
support the W98SE platform because then you wouldn't need to upgrade your
platform to the latest and greatest (??) Windows Vista at great expense.

The garmin topo stuff and roads and recreation will get you along most of
the Forest Roads and scenic byways.  The city select will do the rest and
generally you don't need all of the applications/maps at once, unless you
drive really fast.

And for the GPSV it has the compass mode in which the device functions as a
tracking compass without a map.  Very handy for GeoCacheing, almost dead
reckoning, and other frivolities of that ilk.

HP long ago designed and made a dandy little critter called the HP 800CT
Laptop.  Way ahead of it's time.  Occasionally available on the used market.

We should remember that the GPS system includes the device AND maps as
separate entities for best results and updatability.  The PC acts as an
'intelligent' interface to the GPS and Mapset offering better control and
visibility.

However like Loren mentions, for the old fox among us, presbyopic assistance
measures will eventually become necessary.

Look into OPTX brand lenses.  They act as an attachment to your existing
sunglasses.

Al (tying on those size 24 flies to 6x leaders in twilight requires 3.5
magnification, normal 'opteration' only needs 2x)