The one thing you should have unless you are a weight lifter
with good extended control is a transmission jack.  The
trans weighs about 285 lb with converter.  Mine failed at
138K after abusing it with a couple of 10k pulls thru the
mountains.  I had maintained the trans with regular fluid
changes.  When my problem started, I chacked for seceral
quotes to get the truck repaired.  With most running at
least $2500 at the time, I decided the worst I could do was
lose a couple hundred and a weekend to do it myself.  I
bough a transmission jack at Northern for a hundred which
would not cut it in a full time shop but, did what i needed.
I already had a clutch pack compressor that I used with
other Ford and Mopar units.   All I needed was a set of very
heavy snap ring pliers that I found at Sears on the rack, a
reverse pack compressor and repair parts.  I fashioned an
intermediate clutch pack compressor from a couple of 2x4's
cut to the proper length and clamped across the front of the
bell housing with a short hydraulic jack between them to
compress the pack - worked like a charm for far less than
the pro tool at $200.  Beyond that, you need a good ATSG
manual for it, a good assortment of ordinary hand tools and
patience.  I did all of the updates and added a shift
improvement kit for under $1000 including all parts, all
updates and the tools I bought.  The parts supplier I used
does a lot of inhouse rebuilds for racing applications.  He
rebuilt my torque converter with the heavy duty LUK clutch
for $230 of that $1K as opposed to the Ford price of over
$600 at the time.  Time wise, it cost me a 4th of July
holiday.  If you live near a large city, there may be a
trans parts warehouse supplier around.  I have used TPU here
in Forest PArk, (Atlanta), GA for years.  Shane can tell you
everything you need and ship if needed.  APD is also very
good.  Transparts has a warehouse on the other side of town
and are less friendly to the DIY'er.  I can't say my trans
will last a long as the original since I only have about 80K
on it since rebuild.  I have occasionally abused it a few
more times by towing way over weight with no problems.

While you are there, take advantage of the opportunity to
replace the engine oil pan gasket and the rear seal. The
rear seal requires the trans be removed t replace and the
oil pan gasket tend to work their way out and leak around
140-150k miles.  Use the late style Felpro or Motorcraft
gasket with the metal plate reinforcement.  You should also
consider replacing the engine and trans mounts while you are
there.  These also tend to give way on the top side of 150K
miles.   Oil pan removal and mount replacement require the
engine be lifted and the exhaust header be removed.  Header
removal is also required to remove the trans.  If you remove
the upper intake which takes hardy any time at all will
allow you to lift the engine high enough to remove the pan
and the engine mounts.  You will also need to remove the fan
schroud.  I used a cherry picker with the equalizer and held
it by the exhaust manifolds.  Two things about the upper
intake are you will need a long 1/4: drive with a Torx bit
to remove the center bolt down between the runners and you
must be careful not to pinch the plactic vacuum tubes at the
rear of the manifold.  I should also point out that the PCV
valve is on the top rear of the block behind the manifold.
This is a good time to service it.  At your mileage, be sure
to replace the filter in the hole under the PCV valve.  You
can extract it with long nosed pliers (needle nose).  This
filter tends to plug over time and cause crankcase pressure
which make seals and gaskets leak as well as increased oil
consumption.

There!  You have my list of "while-UR-at-it" recommendations
based purely on The College of Hard Knocks experience.

Good luck

Lugnut

BTW, upper intake torque is critical.  You will need a
torque wrench in in/lb's to do it.  The oil pan gasket is
also this way. And, make sure you use a flat surface to
flatten the oil pan flange around the bolt holes as
necessary just in case someone has already overtightened it
to fix a leak with the original gasket.