If you go the route of ripping up boards so you can stagger them to look like they were 'originally installed', you'll have to remove boards from BOTH sides of the 'blank strip'. This is a lot of work. It isn't enough to just move boards from 1 side. So you're looking at DOUBLE the work. (If you don't do as my suggestion states, you'll have a seam line running the length of the room.)
This is why I suggest you consider a custom-plank to fill the gap. Just 'square off' the floor-board-edges (being careful of nails), and custom-cut an oak plank (or whatever) to fit in there. Stain and finish to match (using scraps to start, and err on the 'darker side' when staining.) Later, you can rip it up and stagger if you want. Or, you can simply buy a nice area rug (with vinyl padding underneath) to cover most of the filled gap.
This is a VERY common situation and is costly to have a Pro make good. It's ALL labor. Sometimes, they'll stagger their seams on both sides of the gap, and then install NEW boards and suggest you have the ENTIRE floor refinished (to match.) Again, it's costly BUT doable. If you're going to live there for the next 10-20 years, go ahead and have the job done right. If you're undecided at the moment, do MINIMAL cuts on the floor to square it off and insert a custom-cut piece of ANY wood until you decide what to do. (BUT, before you cut, DO find out if you can get a 3/4" thick piece of oak. It can be planed if it's too high. I'm sure you'll need more than 8'. Make sure your planks are tongued and grooved at the ENDS; not the sides where it meets all the floorboards. Be SURE to let the plank get 'acclimated' to your home BEFORE you have it cut and planed.)