Lost Creek Wilderness is pretty, has respectable fishing, and has the virtue of being close to my house, so it is one of my go-to places. It is also easy to link trails together into a loop of almost any length you like. However, it is NOT the hike for classic alpine high-country Colorado scenery, if that's what you're looking for. So I have to ask- what are you looking for?
Coming from Oklahoma you could hit the Sangre de Cristo Wilderness, Great Sand Dunes National Park (GSDNP-which also includes parts of the Sangre de Cristo mountains), or the South San Juan or Weminuche Wildernesses quite easily. Just aim for Walsenberg, and thence to Alamosa. Epic hikes in these regions are beyond counting.
Here's a short semiloop I did in the South San Juans:
In the Sangre de Cristos you could hike Music Pass as an over-nighter, perhaps even drop into the Sand Creek Drainage on the other side to putter around and camp for the night, then hike back out the same way. The nice thing about music pass is that as long as you have a 4WD vehicle you can drive to about 10,000 feet, then just hop over the pass and putter around the drainage. Lovely mountains, a couple of lakes, etc. I might put this high on my recommendation list as an easy place to hit from Oklahoma, but it isn't a loop.
Here's a trip report of mine for a short Sand Dunes hike:
And there is some more about a Sand Dunes day-hike later in my old Grand Canyon trip report:
A wonderful idea, but admittedly not a loop and you'd need to get a shuttle, would be hiking over music pass, down Sand Creek, and out to a pickup in GSDNP. That could probably be done as an overnighter, but might be more pleasant as a long weekend. You could easily arrive late on Friday and hike over the pass to camp by Sand Creek, then camp the second night somewhere north or northeast of the Dunes on the Sand Ramp Trail- there are several campsites. This would make most of the hike a gentle downhill, and I think you could easily make the Point of No Return for a pickup my mid-afternoon Sunday.
If I were in the country I'd offer to shuttle you (I live in Colorado Springs) but I'm not. Sorry.
I recall researching loops int he Sangres a while ago, and unfortunately due to the unique geography there aren't many. I'd need my maps to remind me of them to recommend them, but you can find them on the Sky Terrain map easily. And the Sangres are scenic as hell.
Then, for post-hike recovery from any of these, there is a geothermally heated pool in Hooper, just north of Alamosa.
Or, hell, you could combine the hike and a hot spring by hiking to Rainbow Hot Springs in the Weminuche Wilderness. It's about a day hike to get there, stay overnight, hike out. I'm not sure about the mileage, but IIRC there are opportunities to make that a loop. (Again, I'd need my maps to verify.) The place is infested with nudists, though, so if you are of delicate constitution- you have been warned.
Seriously, epic hikes in the region are countless. Tell us what you're looking for. Is a little elevation gain OK? Or would you rather limit it to 3000 feet or so? Or 1000 feet? Do you want well-maintained trails, or are you okay with a bit of bushwhacking or route-finding? Do you want to climb to an epic altitude, or do you want to keep it below 9000 feet? Or would you like to bag a 14er.