[quote=@Necroes]
despite the fact he made up some random, non-cannon ship that can't exist in 40k, yet decided for whatever reason not to make it at least capable of interplanetary travel.[/quote]

It wouldn't have become stuck in a spacehulk otherwise.

[quote=@Necroes]
And, no. The machine spirit would not accept us. It's a computer, they don't do that without being hacked. 
[/quote]

There is no AI in the Imperium of man. Machine spirits have wills, but humans call the final shots. The crew and the ship would have to communicate with each other. You sound like we would have a chance in hell of boarding without human detection.