Lilly- in following your posts, I know you are relieved to have found this community of cat lovers. I also know that you are aware of the large problem of cat over population that is literally world-wide. These "woods cats" are lucky they found a benefactor such as you. I do urge you that once these kittens get weaned off of mom, you take her in to be spayed as quickly as possible, making her one less female cat that cannot add to the problem.
And although we celebrate each litter of kittens that is brought to this board, and there are many members that will help you every step of the way if you need it, we are much more celebratory to learn of spays and neuters of strays and ferals and shelter cats!
Oops! I see now where you say that these will be the only kittens in your immediate future- good for you! But I leave this comment up anyway because it it the strong stance of this board, to do our best to stop the feral cat population when we can.