Would expanders or multiple surgeries help me achieve a K to KKK breast size?

Usually, the  volumes that you mentioned in your question are achievable (if possible safely) with multiple operations. In my practice, the use of overfilled saline filled implants, accomplishes the goals of most patients who are looking to achieve the “extra large” sizes.  You may find the attached link, dedicated to “extra large” breast augmentation outcomes, helpful to you. Best wishes.

There are no breast implants available to achieve the size which you desire.  Overfilling of a saline filled implant, while possible will create a very unnatural and round breast shape, thinning of the overlying skin and a high risk of complications in the future.  

Your problem is not expanders but finding implants made in the US that are that large and physicians in the US who would use implants made elsewhere that are not FDA approved. I would not recommend trying to go that large or going to an MD who would consider it.

Dr. Corbin