I don't know that Dakota's have any specific problem areas.  Does the
'97 have a "push button" transfer case?  Make sure it'll go into 4
high/4 low and that it'll actually spin the front  tires in gravel.

Otherwise, just do the standard inspection.  Make sure everything
works.  Check all the fluids.  Check for bondo/paint/body work.  Etc.

-rev

The rear axle may have some problems in the near future as the 9 1/4 axle
used in the Dakota and 1500 series ram tend to have no so great bearings.

I had a 96, in over 120, 000 miles the only problem I noticed was, like
TBone says
was the rear end. It was starting to make noise when I sold it.
Other than that I think the only thing I replaced was the water pump. It was
a great
truck.
Tom

I've got a 97 Dakota 2WD, 3.9, AT. 197,000+ miles.

Water pump, AC condenser, heater core, pinion seal (which wiped out the
bearings in the rear end), exhaust, and brakes (a couple of times, at
least).  The guy who owned it before me replaced the timing chain and gear
set as preventive maintenance at about 100,000 miles.  I'm in the process of
replacing the rear axle speed sensor.
Other than oil, filter, tires, and spark plugs, that's about it.

For the miles I've put on it I'm happy.

Ken

got a 97 4wd 107,000 mile  replaced muffler and water pump  bought it
at 77,000 miles  
body still looks like new