The short answer is no. When You enter the a portal from the nether, on your way to the overworld, Minecraft calculates the primary portal coordinates with this generalized equation:
{X, Y, Z} → {floor(X) × 8, Y, floor(Z) × 8}
The game then checks for an active portal in a 128 block radius around that location. Given your nether portal coordinates:
X: -70; Y: 72; Z: -139
Your overworld portal must be within the following horizontal bounds:
X = -688, -432
Z = -1240, -984
Remember, any overworld portals within 1024 blocks of each other will link to the same nether portal, because 1024 blocks in the overworld = 128 blocks in the Nether, and the game checks for portals in a radius of 128 blocks.
If you build a new nether portal at the blaze farm and destroy your old portal, your main base portal will probably link up to your blaze farm. However, when you attempt to go back to the overworld, Minecraft will look for a portal within the above bounds and create a new one if it doesn't find one.
Your best option is probably to build a rail line from your current portal to the blaze farm. Ghasts can destroy any block with a blast resistance below 20.17, but they won't shoot at you without a line of sight, so you can make an inexpensive safety-tunnel around your rail line with pure Netherrack.
You can also build a more scenic tunnel with stone, glass, leaves, fences, etc, since Ghasts cannot "see" through transparent blocks.
Best Answer
I couldn't find anything on the wiki, I can't say for sure but I'm pretty sure they've never stated anything much about the history of ghasts. I think that the idea behind it is that Ghasts are like ghosts, and the Nether (where they are found) is like Hell, so someone lived (in the overworld), then died and became a ghost living in Hell, and when you bring them back they are returning to the overworld, where they are originally from.
Or as others have pointed out in comments, it's possibly referring to the overworld as your home (and assuming you don't live in an awesome nether fortress), this is more likely now that I think about it, although I wouldn't rule out my original explanation either.
But I don't think that canonically they are 'from' anywhere, they just spawn naturally. Minecraft doesn't really have lore is the thing.