US 15 S Lane Closure, Gettysburg to MD

I see on a post and the PA highway site that US 15 Southbound is only one lane from around Gettysburg to the MD line.

I was planning to take this on a Monday early July pulling 27'FW. Ultimate destination Williamsburg.

1. Is this a big conjestion?
2. Any suggested alternates? I-81 appears okay from Harrisburg south.
3. Does this continue in MD also?

Thanks in advance.