Fair enough; when I reached out to schools within commuting distance of me (the general NYC area), none of them offered any kind of part time plan for Mathematics or Computer Science (the only fields I'm really interested in).

Sadly, there are not a ton of universities that offer an online PhD in CS or Math, meaning that I was limited to what I could easily get to via train, at least in regards to schools in the United States. Eventually I found one school in England that was willing to let me do a part time PhD online, which is where I'm enrolled now.