Have come upon 2 dwarf ruins that apparently I need a key for to enter. Am I to assume these are quests I need to find first?
Also the dwarf ruin to the far north near the lighthouse murder quest that the expedition apparently did not fare well at. Am I ruining anything by exploring it on my own (I stumbled upon it) or should I have poked around for a quest to send me there?
Whenever 'my' Dwemer ruins needed to be opened with a key, there was a quest behind it (main quest, even).
As I haven't found a Dwemer ruin near the only lighthouse I discovered so far (265 hours in now), I have no idea if romping through it would ruin a quest. Generally, I was lucky - I have yet to ruin a quest by visiting a place I need to visit later on, so I have no hesitations to visit all the places the moment I discover them.
Also the dwarf ruin to the far north near the lighthouse murder quest that the expedition apparently did not fare well at. Am I ruining anything by exploring it on my own (I stumbled upon it) or should I have poked around for a quest to send me there?
It's really up to you since (AFAIK) Skyrim allows you to successfully complete quests which you stumbled upon rather than received. My personal policy is to discover locations but not explore them until I find a quest connected with those locations. You should be able to explore those particular ruins safely and the background story will reveal itself before your eyes. However, the plot of the story can not be resolved without an object received from quest giver but you should be able to finish it later.
Which brings me to another small gripe I have with Skyrim: quests givers for many locations are miles and miles away from those locations. For example, quest giver for the Dwemer ruins Harlequin asks about is located almost on the opposite side of the map to those ruins.
This means that, rather than being able to systematically explore one area after another, you either jump all over the map or let those quests accumulate in your journal until you reach quests areas.
The only problem with your approach Zahratustra is that their is at least 5 dungeons which have a self contained quest inside them. These normally start just inside the dungeon rather on the outside.
You are very right bjon. This is how you can get at least two possible followers.
I haven't expressed myself well. What I should have said is that, when I discover a new location, I do enter it but don't explore it very far unless there is a quest giver within
I look in the guide when I stumble upon a new location. i don't spoil myself, but just look at the heading, and see if it lists a related quest from elsewhere. If it just says dungeon quest or nothing, I go in. Otherwise it's a "save it for later" location.
Also, I'd like to add you can use the UESP wiki for a similar effect. Just search for a location and avert you eyes from anything besides the "related quests" section.