Skeleton key rate needs to be upped, but you're just having bad 3oC luck, most people get 1 every 5-7 3oC. You also can get 400 light with random crucible drops, crucible nightfall, iron banner, archon's forge, and iron lord bounties. Solo playing really isn't that bad, especially since the game was meant to be social. Why play for light level, if you don't even like the activities where light matter?