I would honestly stray away from doing Xav quests unless you have your third class and are willing to level it. Only do the dailies there on your primary and secondary.
At 43 it appears that you should be able to do quests on your Primary Knight in Dust Devil Canyon, which should take you to almost 50, if not 50. As for your Warrior Secondary, you should be getting dailies to level him up to 45 and then you should be able to step into Dragonfang Ridge.
See this lovely post that Yrcanos built for me that I use:
Level 50 and now im lost. HELP!!??