I'm just surprised at how captivated I am by this show... Yesterday, I didn't blink for what felt like the full hour as I was consistently looking for clues or foreshadowing..
I'm not so sure that Rust or Marty is set on committing suicide after solving the case, but I do feel as if they've succumbed to the fact that what they're going after may cost the ultimate price. What does seem clear to me is that Carcosa is liken to Heaven and the Yellow King being the "God" of Carcosa; an ultimate destination. The old lady saying that Tuttle had multiple kids with multiple women because he viewed the mothers as too used for him to enjoy was telling as I think it puts him directly into the cross-hairs of the journey Rust and Marty are on.
Also, Maggie seems to continue to seek a comfortable answer from Rust regarding Marty; she asked Rust about Marty's infidelity before when she already knew. I think that Marty dies at the end simply because Maggie asked Rust (she already knows the answer). Where Marty's daughter comes into this is still up in the air, but it would help explain a lot if she was subjected to this abuse by Maggie's father himself or by being exposed to the Tuttles through him...
Another thing I was confused about... The end with the landscaper. I just didn't catch the meaning... He was definitely mowing in a "coil" pattern, so there is something to be caught there.... Have we seen him before?
Edit: Many bloggers seem to think the lawnmower guy is the spaghetti monster... If the spaghetti monster is so diabolical, I don't see him being as dense as this lawnmower guy... Just my opinion..