The DC travel function, along with your DC filling up more over time, is certainly a helpful trick to have up your sleeve. SassyAssassin mentions another powerful one, which is the Party Finder tool. The game never directly points you towards it, but you unlocked it ages ago. Basically it allows you to advertise content you would like to run and pre-build a party to do so with. Other players get a bonus for helping first-timers do most types of content, so these groups can sometimes fill very fast. This can also be used to form groups planning to use one of the alternate rulesets the game supports - including the "unsync'd" setting that would potentially allow you to tackle some of these older instances with 1 or 2 higher level players using their full power to easily defeat the enemy.