Cool, my Mother In Law stays there quite a bit and we've been to that Wyndham often. It's a nice place. You gonna' head over the to Opry for a night? The Opryland Hotel is pretty amazing to see (don't eat in there though ... not good enough for the money IMHO). But you're in Nashville - plenty to do and eat

If you've never been, check out the Wild Horse Saloon. During lunch hours its family friendly, not that wild at night but it is a bar and VERY Nashville. I live down in Murfreesboro, plenty of good stuff down there too. Stones River National Battlefield is pretty interesting if you're a history buff.
I'm going to try posting map links to three areas for you to consider, they're all mapped from the Wyndham but a put two of them in because they're on the way to Murfreesboro or closer to Murfreesboro. Roads down here are kinda' nutty (traffic engineering is not a strong suit of this area), so it takes about a 1/2 hour to get anywhere.
LInk #1: Cook Public Use Area:
https://www.google.com/maps/dir/Wyn...1bd00efc59b2a223!2m2!1d-86.596842!2d36.134873
This is a small public use area, but free to launch at. You're at the north end of the lake, very BIG, very pretty and not far from the Dam (for interest) and Nashville Shores (watermark if ya' wanna' go play). If you drill into the map and run your finger across 9 O'clock from Cook PUA, you'll see Elm Hill Marina. It's a beautiful marina and a great place to launch, but they charge ya' $5 to launch. Closer drive from the Wyndham, so you can pick which you prefer.
Link #2: Hurricane Creek Recreation Area:
https://www.google.com/maps/dir/Wyn...:0xd9aa6261c723cf75!2m2!1d-86.559!2d36.049646
This is my favorite spot to go in. Four Corners Marina is just across the inlet from it (very nice marina), and it's free to put in here. You're halfway through the lake, so come out of the marina and turn left ... you go into the big open waters of the pretty end of Percy Priest. Turn right, and you go into the (relatively speaking) tighter, but generally less occupied waters of the South End. The north end is prettier (IMHO).
Link #3: Fate Sanders Marina
https://www.google.com/maps/dir/Wyn...0x989f8c04027862b!2m2!1d-86.486716!2d36.04218
This is where I go in most. From my house in Murfreesboro - drive way to wet hull - is about 30 minutes, and real easy. There are a couple of day use areas around as well (Poole Knobs and Stewart Creek I've used - Poole doesn't have a courtesy dock FYI - and Lamar Hill I haven't used), but Sanders is free and pretty big. Lotsa' fishing tournaments out of there though, so 4PM weigh in can be a little raucous. Good water, it's a little "muddier" looking down here closer to the river entry but still a nice lake. Nothing to be afraid of. Just watch the bottom, like I said: channel markers and hazard markers all the way up the channel.
Some of your Army buds fly MedEvac outta' Smyrna Regional just off the lake, so you can wave to the BlackHawks overhead too
Another lake to look at from Murfreesboro is Normand (Manchester, TN). Not as well known and not as big, but there's not many people out there either. It's a nice pretty lake. From Nashville, you also have Old Hickory Lake (which I've not been on) and about 1.5 hours away is Center Hill. Center Hill is a nice day trip if you want. The lake is VERY big, and VERY pretty and has some interesting features The link below is Fanchers Water Fall which we were able to boat up to 2 years ago (not sure what shape it's in now):
https://www.google.com/maps/dir/Wyn...552e0ce64b3ec51e!2m2!1d-85.666284!2d36.004156
That link goes to Johnsons Chapel - a simple no dock drop in we've used. Sligo Marina and Cookeville Marina are in that area and nicer to use. I've used Sligo, but it's a longer run up to the falls area, and tough to get into. I've never been in Cookeville Marina (But it looks nice from the water). I can't remember if the falls is down Lafty Hollow or Moose Hollow. I think it's Moose Hollow.
Y'all come on and have a great time down here. It's a beautiful area. Let me know if I can point ya' in some other directions.
Thanks for your service, by the way. I bet ordinance disposal has to get a little dicey every now and again ... and a little fun now and again. I get to work with the guys up at Ft. Campbell every now and again, and pretty regularly with the guard guys here in Smyrna. They've always been great for our cadets (Civil Air Patrol), and helping us train.