Replacing water pump would be a good idea. Make sure it timings are
correct.

Not sure about the 2.4 but the tool for 2.0 is a threaded rod that releases
the tension on the tensioner so that the belt can be removed.  When putting
the belt back on there are two ways to set tension the first is with another
special tool that spans the holes in the tensioner roller and you adjust the
torque to get the right tension.  OR you set the gap in the tensioner -
feeler gauge work - this is the way I did it takes a few try's but works
great (this also how you check to see if the torque is correct, so why not
do it from the git).

As far as the water pump deffrinately replace at 120k but 60k, I think that
is your call.

Follow the procedures!!!!  When reinstalling the manual says to verify the
timing, rotate the belt and verify again - do it, the belt may jump one
tooth on the intake...

Just got done with mine, only due to a blown head gasket, due to bad
thermostat, which due to the heat broke that little plastic valve off
the radiator cap...jeez.
You need a big vise to set pin on auto-tensioner, then stick a nail
thru the holes. Took mine to a small mechanic shop.  I didn't have the
special tool to torque tension, just pryed against water pump w/
screwdriver good & hard then tightened center bolt.  Then pulled nail
out of auto-tensioner with only some resistance.  Seems fine to me.
Do you have the link to the online service manual?
http://www.fast-4ward.com/3GsvcManual/preface.pdf

I didn't change the water pump b/c I also only have 58K,  That would
be pretty sad for it to be near done already.  Also did't change the
"B"-T-belt.  Yes, 2 t-belts.  A little one behind the main one, for
the counter-balance shaft. Have to remove the crank sprocket to get to
that one.  I just chkd for firm tension, not devasting if that one
fails (uh,well, knock on wood, if it tangles in the other one)

Tools: racheting box wrenches

Tip for the water pump pully bolts:  hold the pully still with one of
the belts, pulling it over the motor mount for leverage.  Then o/c the
motor gets jacked & mount removed.  Then I couldn't get pully out past
the frame.  I bungee'ed it up out of the way so I could work on the
t-belt tension.

Good Luck
Steve