Grand Ole Opry is a lot of fun. In addition to good music, they offer backstage tours.

Country Music HOF is great. Spent a couple hours there last year.

The nightlife is great. Music everywhere. Plenty of country music everywhere but also other genres. I've caught some really good blues acts at BB King's.

Check Jack Pearson's schedule. He usually does a few club dates a month.

Several songwriter venues if you're into that. Good stuff.

Recording studios everywhere.

You HAVE to hit Hattie Bs for their Hot Chicken. It is off the hook!

Been to Nashville several times since I retired four years ago to catch some shows.

The Country Music Hall of Fame is incredible. Even if you are not a big country fan, the historical value of visiting is great. I also enjoyed visiting the Johnny Cash Museum. Absolutely worth checking out.

Can’t say enough good things about going to the Ryman, The tour is excellent and it is one of the most unique places to see a show in this country and certainly one of the most iconic. My favorite venue to see a show in this country.

Third Man Records was tiny when I went and I heard it was expanded recently. Go into the recording booth and record a 45.

You're getting some good advice. I was there last month. I go visit there every 8 years, or so.
It has explode downtown from 2009. The Broadway scene, which is the main drag through Nashville, is insane these days. Basically like Beale St in Memphis, all bars.

I would second the advice on visiting the Ryman, & the CMHofF. I'd include Tootsies & Roberts which are two of the old authentic watering holes, the new Johnny Cash/Patsy Cline museum on 3rd St, I believe, just off of Broadway, & Ernest Tubb's music store. Nudies bar is cool and new. The food at some of the smaller bars was fantastic.

Hot Chicken!

Country Hall of Fame is cool....there's actually an exhibit here called Armadillos & Outlaws that is centered around the 70's uprising in country music....it's REALLY cool and totally worth it.

If you've never been before, check out the Broadway strip but it's REALLY touristy. The best spots to hit are Robert's Western World and ACME, they both generally have the best music going on that isn't really bro(ish) country. Robert's usually has some killer western swing bands.

Bluebird Café is really famous for kind of inventing the "Songwriter in the Round" show, and it's pretty cool. Lotta history there. The Listening Room also does songwriter rounds pretty frequently.

I live in East Nashville and there's some great music venues over there. I'm taking part in a Drive By Truckers tribute/charity show at The Basement East on Saturday night with a ton of East Nashville musicians. If you like DBT, that'll be a cool hang.

The Ryman is always incredible if you can catch a good show there.

Hot Chicken......Hattie B's is good, I like Prince's better personally and you won't have nearly the wait that you will at Hattie B's.

Guitar stores....if you're a player, we got the best around. Carter Vintage and Gruhn's are must hits. Leave your wallet at home though. They're really dangerous places.

Record stores....hit Grimey's. That place is the sh*t.

Red Door Saloon!

Showcases of new artists at a venue called 3rd and Lindsley. The Sheepdogs will be there Sunday evening.

Bring an extra liver!

And I would add the Musicians Hall of Fame and Museum. It's in the lower level of Municipal Auditorium. Exhibits and displays of the folks who made the music for the artists you know/knew. From the Wrecking Crew to the Swampers to the A-team and more. From Muscle Shoals to Motown, they have the gear that made the hits. A few years ago, I took Jules (slidejules) and his wife Lorna there and the owner unlocked a display and handed Jules one of Jimi's guitars and told him to play for a few minutes. Jules was just a little overwhelmed. I would also add the Station Inn to the possible club visit list. It is to musicians what the Bluebird Cafe is to song writers. You literally don't know who might be there and/or playing there. They also have one of the rarest sights you'll see in downtown Nashville, free parking!
And for hot chicken, I like Bolton's on Main Street. Or 400 Degrees, or Subculture or ......... (there are currently close to 50 places serving up the bird, but Prince's and Bolton's are the old guard)
Acme Feed Store has a great Saturday morning brunch and band. Haven't checked their schedule this week, but you can regularly catch Pat Bergeson or Guthrie Trapp holding down guitar duties on the weekend brunch show.
Eat your Wheaties and take your vitamins, looks like you could easily have a full dance card!

Thank you all so much for the replies. Clearly, I will be able to only scratch the surface on this trip, but I have some great guidance. Much appreciated.