1)
What are "Migdol", "Nof" and "Tachpanches"?
1.
Radak: They are cities of Pharaoh's kingdom. The Torah mentions "Bein Migdol u'Vein ha'Yam" (Shemos 14:2).
2.
Malbim: They are fortified cities.
2)
What is the meaning of "Hisyatzev v'Hachen Lach"?
1.
Rashi: Stand facing the war, and prepare!
2.
Malbim: Stand in your place to fight for the cities. Do not go out to confront the enemy, for "Achlah Cherev Saviv."