1)
Why did they agree to declare him king? Before they called the Navi a lunatic!
1.
Malbim: Hashem put to their hearts to consent.
2)
What is "Gerem ha'Ma'alos"?
1.
Rashi citing Targum Yonasan: They are steps made in a way that reveals the hour of the day, based on which step the shade reaches. Gerem is an expression of indentation. Also Hagramah in the laws of Shechitah is based on this; he slaughters and descends (the knife passes from one ring of the windpipe to another). [Gerem] looks like a mound above.
2.
Radak: It is the top step.
3.
Radak citing Targum Yonasan: It is a stone on which the hours of the day are marked (a sundial).
