99 GMC Sierra... oil leaks, intake manifold, knock sensors, valve covers and other miscellaneous things

Not too long ago, I finally had some free time to work on the old beater truck I bought about four years ago.  It's had an oil leak that's been there since I bought it.  Not a bad one, just a drip or two after I had driven it.  After a while, those drips turn into a big mess on the garage floor.  While trying to figure out exactly what could be causing the leak, I discovered that it could be one thing or several different things.  I made up a plan of action, ordered the parts I'd need and when everything arrived, I got started.  I decided to film parts of it so I could let you in on what I was doing.  The video is around 20 minutes, I hope it helps if you're experiencing anything similar.