Finished replacing the camshaft plug, solenoid holder gasket, solenoid o-ring, and oil pressure sensor re-sealed with RTV sealant around the threads.
There actually was plenty of room to work! It wasn't bad at all. Take a look, removed the intake piping along with the main engine wiring harness stay bracket. Unplugged the sensors and solenoid...
Unbolted the solenoid and holder, along with the oil pressure sensor...
Then, just using a flat head screwdriver and a hammer, I gently tapped the bottom edge of the camshaft plug. Since it's made out of steel and it's very rigid, pushing the bottom end inwards made the top end come out just a tiny bit. I then put the screwdriver on the top of the plug, and gently hammered downward and outward. The plug started coming out. It was actually very easy. Here it is ready to be pulled out.
And a shot of the plug removed. You can definitely see that little dent/ding on the right side, but it doesn't go into the mating surface so I don't think it was causing the leak; rather, the original seal is just old and the rubber coating is worn out.
Installation of the new plug was actually a lot easier than I anticipated. Before putting in the new OEM plug I bought, I tried out a Fel-Pro plug to kind of get the feel of pushing it in. The Fel-Pro plug was a tiny bit more loose, whereas the OEM plug was a little tighter. Even so, I was able to push it in with using just my hands and a little bit of patience. It really wasn't that bad at all. Judging by the looks and the feel of it, it seems very well leveled in the hole - and not too deep. The top of the edges are just at the very end of the bevel, just like the original one was. Nice. Take a look....
I pulled out the solenoid to check the o-ring, and it looked fine. Even so, I replaced it with a Viton o-ring that was a tiny bit thicker... It slid in nice and snug.
I reinstalled the oil pressure sensor after cleaning off the threads and applying RTV sealant on said threads...
And finally, I installed the solenoid + holder back onto the head complete with a new OEM gasket. According to the FSM, the 4 10mm bolts should be torqued down to 7.4 ft-lbs, so I did so with my nifty little 1/4 drive Tekton torque wrench....
All in all it took about 1.5 hours from start to finish. This was a pretty dang easy job. But, hopefully I'm not celebrating too soon. I'll check back on my work to see if it's still leaking over the next several days. Finger's crossed. Other than this, I've driven about 250 miles since I put in the Seafoam. I figure I'll give it a total of 500 miles before I change the oil, as recommended by cardoc and aesthetic.rake, and i'll check the level before draining it to see how much I've lost. I'll put in conventional oil, add in more seafoam, then run it another 500, then change back to synthetic. Hopefully this does the trick.
Thank you again for everyone's help. I hope I don't need to rebuild or replace the engine; but, we will see!