That said, font tweaking on the PW2 (especially, it's been wonky ever since the K3, but it's gotten more annoying on the PW2) is *NOT* for the faint of heart (unfortunately), so, er, as much as I'd like to tell you: "it's easy and safe, go for it!", I can't in good faith do that without warning you that wonderfully weird things might happen for no good reason if you go that route.
(I've already said this multiple times, but I completely get why the ALT_FONTS thing was killed on the PW2: it might have been nice, but it was also the fastest and easiest way to soft brick a Touch/PW1).
However, all the known issues and limitations, as well as advices on how to best approach the whole thing in the most painless way possible, are spelled out in the font hack thread. On the bright side, most of the potential issues are limited to the setup stage. Once you've got something working, it's pretty much solid

[barring the usual havoc-wreaking of official updates].
TL;DR: While potentially rewarding, this is far from the easiest and safest thing you can do with a jailbroken PW2, and thus might be a bit harsh as a first foray into the Kindle customisation world

.
EDIT: I'm mostly talking about the software approach here. You *can* experience some of the same issues (broken rendering and/or crash the reader/framework/device) with a "simple" KF8-with-embedded font file on a vanilla device, but at least it's limited to a specific file inside a specific application.