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Grind ROC strikes, level up your vangaurd since it's the easiest to level up. Along the way you may be blessed with rng and get stuff that you need. Once you reach the level cap to participate in the VOG raid I would grind the hell out of that especially since they're ranking up the old gear and weapons. It's your choice after that if you wish to do the CE raid to get those weapons and gear but after this next DLC they might be obsolete. Also don't forget to do the weekly heroic and weekly nightfall when you've reached the appropriate level as well.
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now one tends to grind crucible or vanguard strikes to get engrams, rep, and marks - all to be used to grab legendary gear to raise you to at least lvl 27, but honestly all the legendaries that can be bought can bring you all the way to lvl 31 but your main problem will be getting ascendents to lvl your purple gear. basically, the game is now about grinding activities that give you item rather than give you experience, but the latter is still needed to lvl up the former. you basically keep doing this and never stop, it's now always a valid option as end game content. However, once you reach lvl 27, the raids become your best bet but you still need to do crucible and strikes to get the materials needed to lvl up your items. you go from one set of grinding to the other