Update:

I went to the LBS with a spoke & nipple in hand. He was able to get me a set of 36 nipples at $0.16 each for a grand total of $5.76. I got the wheel completely disassembled and will be working on relacing it in next couple evenings. From what I can see, the rim looks to be in good shape and lays flat on a flat surface. I checked the overall diameter in many spots and it was just shy of 25" all around. Looks like the rebuild can begin!