Dungeons are good. Time to travel to the dungeon can seem like a waste though, and then the reverse after each dungeon to go outside and reset is also a time sink.
Just using dungeon queue might be better. Stay in a main city to get the rested XP boost when you take a break or log out. This of course can only work for characters of the appropriate level so you may as well both level new too a together if that's the plan.
There are also items for high XP % boosts. I think the one that trades on the AH goes for 25-50k depending on server and gives 15 minutes of 300% XP. If gold is no issue that will be the biggest help.
Or if endless gold, just buy 4 tokens, redeem for Bnet $, and buy the $60 level 100 boost.
Recruit-a-friend is also an option. This only works if you're willing to pay the $ for a second game and 60 days of game time (30 for benefits, 60 gives the recruiter a mount also). The upside is you can be recruited on the email you already use, add another wow game key and subscription, and then when the subscription and RAF benefits run out you can open a ticket to move the character from game 2, into game 1 so only one subscription is required to play all your characters from one wow account. Or you can leave two games and multibox. Costs extra $15 monthly but a lot of people do it. Share lfr gear, do world quests twice as fast, solo old raids for farming at double the pace, etc. All transmog, mounts, pets, achieves are shared on your email address/bnet account not the individual wow accounts within the email/bnet. This means collections can grow much faster if you multibox two solo runs at a time for old content.
This post was edited by AlanLipp on Sep 27 2017 10:45am