Just wanna confirm that every dungeon in this game is PuG-able!
I just got mine yesterday and all of them are with random people! I’ve to do it all by myself since my friends are not interested in doing dungeons and the 2 guilds that i join transfer away for WvW reasons.
Sometimes, it helps to check that everyone in your group has higher achievement points like those with 1500-2000 and above, since it shows that these people have played the game for quite a bit and should know their class pretty well.