We stayed there 2 years ago. If nothing has changed since then, Runaway Bay is the section of Calypso Cay with rental apartments. I mean real rental apartments. The residents are tenants and live there year round.
One morning when we were leaving, I noticed a cat in one of the windows and commented to my family that it was nice they permitted pets. On another morning we saw a moving van. It wasn't furniture in keeping with what we'd seen in our unit. I had a timeshare tour, so I asked the salesman about it and he said, yes, they rent the apartments to year-round tenants.
There were no elevators in the buildings and we were on the third floor. The apartments were okay, not spectacular.
For the price, we couldn't complain too much. One of the tall high-rises on the Calypso Cay property has the timeshare units. Those were REALLY nice.
The complex has hotels.... Country Inn & Suites, AmeriSuites and I think something else. Runaway Bay is across the street (a small private street) from the hotels and the pool area for the hotels. Runaway Bay has its own pool, but the one for the hotels was really nice. We could use the hotel pool when we wanted.
It's an okay complex, and I can't explain it, but I didn't feel comfortable renting, in essence, a hotel room with others in the complex being permanent tenants. (Okay, I'm a crank.)
If the price is right, give it a try. Just ask them not to put you on the third floor (especially if you have bad knees like some of us.) I wouldn't stay at Runaway Bay again, though.
Hope this helps.