ONE of the most surprising fact about Kryptos is, that nobody has yet discovered the anticipated way the keywords for K1 und K2 should be found. And maybe this missing fact is the key why we are stuck with K4. I don't think, that Sanborn wanted us to bruteforce the solutions (as we did), but somehow left a hint we didn't recognized so far.
Most people believe, that the morse code messages around Kryptos should somehow encode at least the first codeword for K1 (= Palimpsest). That's why the morse code message are often called K0.
The morse code messages are part of two pieces of granit with contained copper plates. I found two very interesting drawings of these two installations from Monet Friedrich on [1]: