I would have to disagree heavily with this because this is the gear you're supposed to farm for excessively. Buying it from the crown shop or from a vendor would completely defeat the purpose and make it too easy to get the items.
You can technically buy it by farming the second chance chest, but there's no guarantee you'll get what you want..
On the same note though, i do feel the paradox gear set should at least be dyeable. It's such a shame that such a good-looking piece of gear doesn't really fit the look i'm going for. A lot of people i've asked in-game seem to agree with me.
Astral Forest drops that hat and boots which are the only good things once again. It's also a pretty easy dungeon to farm. I got my hat on the second farming run and my boots like on the tenth or so. Just team up and stick with it and they will drop.