I'm not sure if you want to "cheat" your way to some faster upgrades. What i did was make two teams ( i have 6 lvl85 mages ) But this will work for 5. Both teams had my paly tank and resto sham healer+ 3 mages. Since I was going to be farming FL trash I knew i needed hit. So I farmed the first boss in HoO for the hit trinket. Once I got it on all 6 mages i had enough JPs to buy some gear. I then used the same two teams And maxed out JPs for normal instances for the week on each team. You see the point.

I know your goal is to just play the mages. If you do that I would do the Hygl quests.. at the end of one of them you get a nice epic cloak. Then do the dailies as well, you will end up with an epic neck in a few days. If you have money to burn, pick up some epics on the AH. For rep grinding, put on your tabard and just go to any heroic instance with sheepable trash and kill/loot/reset.

Another option is to PvP for gear.