To Duo level a Druid/Mage what would be the best option?

Just rerolled on a horde server because I introduced my younger brother to the game, I made a second account on my Battlenet and played with him as a Druid and him a Mage.We got to level 29 and he doesn't want to keep going, it just isn't his cup of tea and that's fine, but I want to keep going. I want to play TBC and on.I'm going to keep leveling this Druid but I was thinking of Alt/Tabbing with the Mage behind and get it to 60 so I can solo some dungeons on it.With Boosting off the table since I just rerolled would the best option be to just quest with both of them alt tabbing and killing mobs at a much higher rate in a party?Or should I look up how to for the Mage and try and go the AoE farming route? I was thinking gather mobs on Druid in Bear form and Mage does all the work?Any tips or thoughts would be super appreciative. Especially any advice on alt tabbing to play two characters at once. (It's tricky but really reminds me like I'm playing a Final Fantasy game or something, Id like to try it with a Warrior + Healer).