I levelled two chars to 89 to do Ahune recently and then went ahead and got them to 90. Here's what I do:
* Kill Isle rares til you get a key, do Super Happy Treasure Run to fill up your elder charms
* Kill Pandaria rares til you get 50 lesser tokens, get 3 Mogu Runes
* Use Isle rep tokens to get to Honored or whatever and buy the 476 belt
* Do world bosses, roll on all of them
* Rent PVP gear for honor points to bump your ilvl up to get into LFRs sooner (also, kill Krasarang rares for 483 world PVP trinkets)
* Do T14 LFRs, roll on every boss
Two weeks of this and my two nooblets are 478 and 477, one of them already has her legendary gem ready to farm 3k VP and the other will this week. These are not new mains I'm trying to catch up, so I'm not investing a lot of time or money. I'm not crafting 496s for them, much less 522s. I'm not rerunning LFRs to reroll on boss drops I really want. But they'll be in ToT LFR this week and pretty close to 500 next week (total: four weeks) with a minimum of effort.
So I guess what I'm saying is catchup is fine, and if it takes you half a year then you should re-evaluate how you're catching up.