Chess solitaire: The King's longest walk

I think I've got 25 steps - it's not brilliant but might be something to start with:

My setup looks like this:

White has only one piece (king) which starts on a1 (blue). The goal is to reach h1 (green).

I made an error with the image in that the knight on d8 should be on b8 and the pawn on e3 should be removed completely

The least amount of steps to get there appears to be:

This position:

requires the following 40 moves to move the king from a1 to b7:

As a bonus, the White king is alone (fits the 'solitaire' theme'), the position is legal, and it doesn't use promoted pieces. The pawn on a5 and the bishop on h7 aren't even necessary, so there's probably room for some optimization.

First solution - 50 moves
Second solution - 59 moves

Current solution - 66 moves (beaten by Retudin - 70 moves and Rewan Demontay - 139 moves)

Moves:

Stealing ideas from Sleafar's first solution, I got to 62 moves. So hopefully someone can better that with the magic 64 or more.
EDIT: Since 62 is beaten by Sleafar, I'll up my score to 70: Earlier I failed to realize a8 could just be a pawn; freeing up a bishop

Addendum #2: With @Retudin's suggestion of placing an additional Black pawn on the bank tank, to the 129-mover, and my idea of moving around a few pieces, we have here a new record of 135 moves, with the king starting in check. The solution is still inherently the same, so there is no need to put it in.

Further Edit: Since there is no need for a unique solution, a further small change presents for 139 moves, with the king in check.

!>

Addendum 8 Hours Later: Seeing as the OP agrees with the presented concept, but not the use of promoted material as per requirement #3, I shall provide the record without the use of them.

As it currently stands, again as of writing, the current length record for this task, however, without promoted pieces in a legal position, is a still astounding 129 moves.

Here is another direct link to it once more. This one is also verified to have one possible solution by a camera.

Branko Koludrovic, Cornel Pacura,, & Arno Tüngler, 496 mpk-Blätter 02/2012, 2. spezielle ehrende Erwähnung, Informalturnier 2012/13 Stipulation (The goal is to reach h2): ser-Zh2 in 129

Solution:

Again, since this is a legal position, and you allow for illegal ones, this is but a proven lower bound!

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I have an answer that shall blow every other attempt here out of the water: 208 moves!

In essence, your requirements fulfill a genre of chess composition known as seriesmovers, which are problems in which only one side moves, with some exceptions on the very last move, and they can't be in check, minus the starting position, and cannot give a check, except on the last move in some of them.

A search of the Die Schwalbe Chess Problem Database reveals that the current record length, as of writing, to move a king to a designated square in a seriesmover in a legal position with promoted pieces, is 208 moves long.

Here is a direct link to it: moves there are in German notation. The nice thing is that this is a computer verified composition, meaning that there truly is only one possible solution,

The stipulation "ser-Ze3 in 208 moves" means this: The "ser" is short for seriesmover, the "-z" part is the accepted notation for problems in which the goal is for one side to reach a certain square, and, lastly, "e3" is the chosen target square.

Arno Tüngler, T140 ChessProblems.ca 13/05/2013, 1. Preis Stipulatiom: ser-Ze3 in 208

Lastly, here is the spoilered solution, but in English notation:

Now, since this is a legal position, and you allow for illegal ones, this is merely a proven lower bound!