1)
Why does it say "b'Seser ha'Har"?
1.
Megilah 14a: She came regarding blood, which comes from hidden (internal) places; she showed Dam Nidah to him (David).
2.
Radak: Due to the mountain, they did not see each other until they met.
3.
Radak citing Targum Yonasan: It is the hidden part of the mountain.
2)
How were both of them descending towards each other?
1.
Rashi: They were on mountains; there was a canyon in between. Malbim - we are forced to say that he already encountered her youths.
