Chattanooga is one option. I love this inn on Lookout Mountain - http://stayatchanticleer.com/

If you did the beach, I'd go to Seaside in Florida but that's over 5 hours away.

Callaway Gardens has a beautiful new lodge with spa and they have a beach on their lake. That's over 3 hours away.

Brasstown Village resort in north Georgia is nice - but again about 4 hours away.

Joe Wheeler State Park is about an hour away -
http://www.alapark.com/JoeWheeler/

There aren't really any "nice vacation areas" within a couple of hours of Huntsville unless you look for a cabin/house rental on one of the lakes in northwest Alabama. Starrs gives good suggestions but I wouldn't call Callaway or Brasstown "luxury". You might look at the Inn at Serenbe just south of Atlanta.

If I were you, I'd head down to the beach. A longer drive but it's what you want to do.

If you want to stay within a couple of hours, look at Starrs' Chanticleer link, or The Chattanoogan Hotel or the StoneFort Inn in downtown Chattanooga.

Meant to type northeast Alabama. Alabama is west of me.

Those are the closest options that came to mind, but I didn't mean to imply they were "luxury". I was brainstorming nice options. The Ritz Carlton Reynolds Plantation at Lake Oconee is too far away. Blackberry Farm is almost 4 hours away - but is truly luxury.

I'm not sure if padams has been to the Lodge and Spa at Callaway but it is very nice - managed by Marriott. I've been very pleased with the rooms and spa and it's not what many think of when Callaway Gardens comes to mind. It's not the Ritz but it's not a typical Callaway lodging -
http://www.marriott.com/hotels/travel/csgak-the-lodge-and-spa-at-callaway-gardens-autograph-collection/

Brasstown is nice too and would be a good base for exploring the mountains.

The best best for "luxury" would be Blackberry Farm, but it is indeed pricey - http://www.blackberryfarm.com/

I'd go for the beach too, if that's your first choice. Gulf Shores/Destin/Seaside aren't prohibitively far away for me, but it all depends on how long you're willing to drive. Nashville and Chattanooga are both two hours away or so. Nashville if you decide you feel like some sightseeing, Lookout Mountain/Chattanooga if you really want a cabin or something.

I totally agree with Starrs. I like the Lodge and Spa at Callaway. If it were me personally, I'd go there while my kids were at space camp. OP's use of the words resort and luxury, however, made me think she might be looking for something more upscale.

When our kids went to camp in North Carolina, my spouse and I went to Asheville. I am a big fan of parent trips ("grown ups camp") while the kids are at camp. Enjoy your trip!

The OP here... thank you all for your very thoughtful suggestions. Just to add a bit more information...our original plan was to drive from Texas (maybe 10 hours), and then drop the kids off at camp in Huntsville. We wanted to limit the travel to another destination for me and my husband since we would have just driven ten hours from Texas.

It appears that what I have in mind really isn't available within a couple hours drive of Huntsville. Therefore, I've started looking into cashing in some FF miles and flying into Huntsville. We can rent a car there and then drive down to the Gulf beaches the next day.

That really makes more sense for us. Just some more background: this will be the FIRST trip we've done without the kids. We've taken them all around the world with us, and we've made wonderful memories. However, this time will just be for the two of us. We want it to be a memorable and relaxing vacation.

Now, I guess I'm focusing in on the closest beach to Huntsville with a lovely hotel/resort on a beautiful beach. Just starting to do some research, but would love it if anyone can point me in the right direction. Thanks, guys/ladies!

I would go to Watercolor.
http://www.watercolorresort.com/

If you want to rent a cottage instead, look at Seaside.

I love the 30a website/Facebook page and it's a great resource for places to stay/things to do along 30a.
http://30a.com/watercolor-inn-and-resort/

Thanks for the background, Kennedy3 - sounds like a good plan. One thought - Huntsville is a fairly small airport, so if the "cost" of FF miles there is huge, you might check out Nashville or Birmingham as well. Both have bigger airports than HSV. Either is still a drive from space camp, of course, but less than ten hours! Anyway, just a thought. I hope you have a great trip!