How can I find the total time on a CD?

Here's my situation: I have several CDs with audio surveillance on them. In total, there are 7, 688 audio files (*.wav format). Boss man wants me to index the CDs, detailing the content, date recorded, and length. Here's the thing: I'm not about to sit here and manually go through 7,000+ files and add up all the time. Some of these files are small! 7 seconds here, 12 seconds there, another 3 seconds here...I don't have the time or patience. So....I need a shortcut. Help!

And if it helps, the agency that burned the CDs made it incovenient for us. The audio files are buried like 4 or 5 folders deep...I have to go through several folders JUST to get to the audio.