Putting the redstone wiring in place required ripping up a lot of the existing blogs. The design itself was easy enough to implement, and any YouTube search for "2x2 piston door" or the like should tell you what you need to know. As per my personal rules, the redstone wires were put on wooden planks. In the picture below, it helps you see where the redstone stuff is. Perhaps the only thing I may not like about this setup is how pistons make noise. Zombie Pigmen sometimes come through portals and if I hear them set off the pistons by stepping on pressure plates, it could really freak me out.
The same door, looking from inside the room. Red carpet leads to it. I again employed stairs to break up what would otherwise be a nearly flat wall. It's nothing fancy, but I like it.
Next was the issue of creating a new portal. I've gone through a lot of hassle with this trying to set up a new portal pair prematurely. The portal in the Nether was linked to the portal at my first base. I destroyed the portal at the first base and returned home. I went through the portal of this base then came back. The game generated a new portal by my first base! Every trip to and from the two bases was about 200 blocks of walking and boating. At one point I even tried breaking the Nether-side portal using a wooden pickaxe, and later lava!
After going through several blunders, I finally had a half-decent plan. Going through the portals I arrived at the accidental portal at my first base and broke it. Then returning to my cave base I crafted a new diamond pickaxe and unloaded everything else except the pair of boats I had made for the trip from the destroyed portal to my cave. I then proceeded to break the portal.
The despawn timer doesn't run if a chunk is unloaded, so I figured I would have time to reacquire the diamond pickaxe if I really wanted to. There was only one way for me to get back to the overworld this time. I dropped the pickaxe into a safe spot away from the lava, then took a nice warm bath.
I respawned back at my cave base, as expected. From there, with another diamond pickaxe, I broke the portal I had been using there, and lit the one in my portal room. Now it was time to make sure this crazy plan was going to work.
It worked, but in the most unusual way. The game put me right inside the Netherrack! I'm literally encased in the stuff. Looking at the surrounding area via Minutor, there's no conveniently located openings within a stone's throw of me. That just means that my Nether base is going to be embedded in the Netherrack. Either that, or I'll have a lot of digging to do if I want to be able to see it. This new portal isn't terribly far from the old one, which means I'll have a good shot at reclaiming the pickaxe.
My next concern was whether the two portals had successfully linked. Going back through the portal I was happy to find I had indeed returned to my portal room! The plan worked!
Basically the last thing I wanted to do with the room before calling it completed was add what looked like spillage around the portal. To give the sense that the Nether was spilling into the overworld, I came up with a little design of Netherrack surrounding the portal. It's asymmetrical, and I like it.
I'm probably going to start working on the Nether base next. It's probably going to be styled after the MindCrack server's Nether hub, with rail lines leading through the Nether to various things. I will probably use it for strongholds, Blaze farms, Mooshroom biomes, villages, and other things.