The market value pretty much depends on the area you live.  The
price for the re-stringing, pinblock and soundboard repairs sounds
reasonable.  If you're lucky all it will really need is repinning
with the next larger size pins.  I've run into a number of the Ragtime
pianos with loose pins and questionable strings; one even had
a cracked bass bridge that I had to repair.  The price your tech
has quoted you, though, sounds more like repinning and not pinblock
replacement, which is acceptable if the pinblock is not cracked.

If you're wanting resale value, it may or may not make any money.
I know this doesn't sound very definitive, but that's the way the
market is.  Piano-wise, if it's in otherwise good shape, you'll have
a very nice piano for that price, much better than a new one.  Of
course, that's my opinion.

Dan Armstrong - Armstrong Piano Tuning & Repair
Pine River, Minnesota