I do think it is feasible, for the most part, but there are a number of factors that can alter how feasible it is. For example, what is your full-time work schedule like? Flexible, or rigid?
I think there will come a point, as you approach the final classes necessary to acquire the degree, that you will find classes that are offered at only one time, one section per semester.
That being said, I do believe it is possible. I am currently operating under that assumption. It is already difficult and I am still near the very beginning of required courses. I'm quite certain that it will only get harder. That being said, I'm enjoying the process as much as I hope to enjoy the destination.