Recovering this old photo

Sorry, I know there's another similar thread; I'll follow it too but don't want to hijack it.

My father has a series of old family photos he wants to scan and save, and I thought I might lend a hand. He gave me a few, the most problematic of which is this one. I scanned it at 600 dpi in jpeg, and then got to work. Noise reduction, levels, curves: in a few minutes, I got a decent enough result - one I can't show you as it's on my home computer, but it isn't really relevant anyway.

My main issue is that the picture is really dark and I'm having trouble recovering detail in the shadows. Obviously I can only do so much, but where in ACR I'd use the Fill Light tool, I'm not sure how I can substitute in PS. The histogram is so condensed to the right that it's hard for me to use Curves precisely enough. I haven't tried the shadows/highlight toll yet but it's next on my list.

Any other tips? Would a dedicated photo shop be able to scan those in 16-bit .tiff to give me a bit more working depth?

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Looks like there's no more detail in the print.
What's not there cannot be enhanced.

Got access to the negative?

I used photoshop. Did a curves and levels adjustment, a bit of shadows and highlight adjustment and removed some of the redish tone...

Nah, the negatives are all long-lost.

I wasn't so much looking to recover the shadows themselves; that looks well lost. But say, on the boy's face, the shadows fall real quick. I was wondering if there was an easy way to make the gradient a little softer, if you see what I mean. And, if possible, to do it over the entire picture at once rather than dodging and burning bit by bit, because I got a few of those to do and would rather not spend hours on each if it can be avoided.

edit: @Edsport: Thanks; that's about where I got too (I added some NR on top to smoothen it a bit). I'd like to bring up the partial shadows on the faces to add a bit more definition, but can't think of any way to do it that doesn't involve local 10-pixel brush adjustment, which is likely to be real long (for context, I have about 200 similar family photos to process).