Chkdsk hangs at "chkdsk is verifying usn journal..."

The longer you use a failing drive the worse and more unreliable it becomes. So if this data is important to recover I would begin backing it up sooner than later. So at this point you might want to skip the chkdsk stuff since you potentially have limited time if the drive decides to stop working altogether.

There are also a number of tools to clone the drive. I find the most reliable to be a tool called dd_rescue. Essentially it makes a bit by bit copy of the hard drive, skipping over any bad or unrecoverable sectors it encounters. This is obviously slow and if the drive is failing to an extreme you might not be able to recover anything.

Another free tool to look at is called Unstoppable Copier. This one is used to recover specific files, which in many cases can be much more convenient than cloning the entire drive (for obvious reasons).

If neither of these tools help at this point, and the data is super important you should maybe consider taking it to a data recovery company.