It didn't take too long for me to encounter my first Ghast. I took it down no problem. But when I wanted to return home so I could resupply, I had a road block...
Here's a cool view of my portal from an elevated position:
When I returned to the Nether, I started hearing what sounded like a wet slapping noise. That's what a Slime makes. But there are no Slimes in the Nether... but there are these guys (I thought they were rare...):
I sliced him up and got plenty of XP from him.
As I explored around more, playing badminton with Ghast fireballs, I noticed a silly glitch:
After exploring for a little while, I didn't find any Nether fortresses. I returned to the overworld and exited the game. Curious to see if any fortresses had appeared anywhere, I went on Minutor (slightly violating my desire to play this map completely legit). As it turns out there was one about a hundred blocks from me, but the part closest to me was encased in Netherrack. After breaking a pickaxe and going to the wrong coordinate pair, I broke into the fortress:
I heard plenty of Blazes around me. According to Minutor I had at least two not very far from me. I didn't really want to battle them so I went on Peaceful mode and snapped this pic.
I could probably make this into an XP farm in the future, as well as a good source of Blaze rods with which I could power my furnaces.
I explored the fortress for some time and decided to start mining it. Once I gathered a large enough amount I returned to the overworld.
I then built a room with Nether brick, glowstone, and sandstone. I also completed the room with light gray wool in the ceiling, and also made a more natural room using cobblestone, dirt, and jack o' lanterns.
Final amusing point: I was doing some mining to gather more coal and stuff (as if I really needed more) and came across a huge coal deposit. It was at least 5 blocks tall and I actually ran into bedrock.