the most time consuming part is proper prep. peanut butter jars are life-savers. label them, plop the parts in, add a little cleaner, and your parts are organized and clean.
the actual in and out of the motor is very quick if you have any clue what you're doing. the highest bellhouseing bolts are the tricky part. took about 30 minutes to unbolt tranny, etc. and remove engine, then about 45 minutes to get the new one in there and bolted up. took another few hours before i had everything bolted up, double checked and ready to run. that was spread out over a year, though. took me a long time to get around to it with my job and weather, but the actual work was fast.