JKII has the great distinction of having subsequent patches being Single Player 'Save Game' friendly ... unlike MoHAA, for example. So I'd definitely recommend patching straight to 1.04.
The Multi-player aspect is not my arena so much, but there are many here who will help you out with things like ProMod.
These forums are full of very helpful people ... you don't have to sort through too much BS here, compared to some places I've seen related to other games. Just the occasional 'sky is falling' thread ...
I also recommend checking out www.jedioutcastmaps.com
for all kinds of maps ... there are lots of great ones out there, from single player maps you actually care about finishing (a rarity for any game) to excellent CTF and FFA maps and more. The only problem with the site is that it suffers from what I'll call pop-up flatulence ... and leave it at that ...