Here is a bit of negative advice (lest I be accused of being a white knight blizzard brown noser etc etc)...5 man heroics (and 'Normal' lev 90 dungeons no longer exist) are incredibly easy and dumbed down (in my opinion even moreseo than wotlk). Some people love that, but I don', and I imagine that if I were solely or mostly interested in those I might be a little disappointed. There are also a bit less 5 mans than you may be used to. I think there are 9 maybe (including revamps of Scarlet Monastery and Scholo) though that number may be wrong.
One thing to consider is there are now Challenge modes of the Heroics, in which all gear is scaled DOWN to 463 (to prevent players overgearing), mob health and damage is turned up, and a timed component is added. It would likely be difficult to find teams for these depending on your realm and you may be perceived as a poor player because you won't have a ton of gear, BUT it would be possible to jump into these with 463-47something ilvl and contribute as gear is scaled down.