With an Overdrive, the only way out is through the car interior. You will also have to remove the ebrake handle and I also remove my steering wheel just for more clearance, but the wheel is not necessary. If you have an engine lift, you can easily remove the trans/OD by yourself with just a couple of choke straps or strong ropes, or grab a bud and the two of you can muscle it out of the car. It is not real heavy, but awkward to grab and move.
Once you have removed the rear transmission mount, prop shaft, and bell housing bolts, you will need to raise the engine a wee bit for the transmission to clear the rear cross frame member. Once clear, it should slide off without too much trouble, however, I have heard of some release problems from the clutch spline. This may require a little more determination, but is doable with a small pry bar used below and then above the input shaft - with a gentle wiggle up & down on the unit.
Be careful of the exhaust system, that you donot overstress the manifold while moving the engine upward. I removed the exhaust support near the transmission rear for more clearance and made sure that the connection was slipping a little when I raised the engine. BTW: use a nice wide board on the oil pan when you lift the engine.
When you remove the clutch slave cylinder have a piece of wire handy to tie it up so not to stress the hydraulic piping, especially if you have the original nylon supply.
On the bell housing, there are 2 - 3/8" bolts at the ~ 5 & 7 o'clock position and all others are 5/16" (if I remember correctly) with exception of the starter bolts. There should be three threaded studs at the top of the engine block. These three studs with the two 3/8" bolts help with alignment on the re-intall. As mentioned you will need an alignment tool to center the clutch before the cover (pressure plate) can be secured. Examine the cover fingers for excessive wear and replace the unit if need be. Mine were almost worn clear through.
OMT: All of the nuts should be on the rear of the bellhousing when you re-install.
Good luck