best way to repair space between hardwood floor after removing a wall?

Hello I remove a wall and now there is a empty gap where the wall studs was placed also the flooring is placed in different directions one runs vertical and the other horizontal I guess being that it was separate rooms and one being smaller the previous owners decided to run the flooring different but now i'm trying to figure out whats the best way to fill that long gap. the floors are not in good shape so they will have to be refinished. I was thinking this might not be worth repairing and instead re flooring with maybe engineer wood panels. what do guys think?

 

I would probably just cover it with a single board until the time comes when you might replace the floor. Lay a 1x6 over the gap, trace the edges, cut out with a skilsaw, clean corners out with a multitool, drop the new board in.