I don't think I have committed to a time frame yet.
Right now I would like to determine if the text says all the land mass was in one place prior to the flood.
And that the land mass was still in one place when the flood took place.
And that the land mass was divided in the days of Peleg.
Lets clear that up before we move on.
I'd say that your interpretation is plausible, but I think it may press the text a bit too far.
Yes, the text says that God gathered the waters together in one place (maqom echad). But the main point here does not seem to be one vs. many. Rather, the main point is that God controlled and tamed the chaos.
Yes, the text says that the land was divided in the days of Peleg. But I think it's a stretch to interpret this as the division of the continents. It could just as well be a large earthquake.