I have to agree, with the shrinking player base the wiki's are just not as well maintained as they once were, which can make things difficult, especially as a returning player to a game that has changed so much.
In my experiences, FFXIclopedia seems to work best for older content, yes as Lyraillis mentioned there have been changes to some aspects of the game and FFXIclopdia has not always been updated to reflect these, but for quest and mission walkthroughs not much has changed. BGwiki on the other hand, has a lot of gaps in its info for older content, and is generally not as detailed, however for the more recent events and content (Adoulin and beyond) it is much better maintained. Nine times out of Ten I am able to find what I need on either one or the other wiki's.
Outside of the wiki, ffxiah is a great resource, if you are having trouble finding out where a specific item is obtained, or what it does, you can generally search for it on ffxiah, and then read the user comments to gain some insight, failing that there are still several XI forums that are quite active, I like ffxiah's and the ffxi reddit page and you can usually get what you want asking on there, sadly ZAM's XI forums are not what they once were (Some of the job forums have literally not been posted in, in years).
____________________________Retired from FFXI ....but for how long this time?