How does "Sechel Tov Yiten Chen"?
R. Yonah #1 Sechel is Emes. Those who hear it accept it without proofs - Emes teaches its path.
R. Yonah #2 Sechel Tov is Sechel Emes, or Sechel that joins to action - "Sechel Tov l'Chol Oseihem" (Tehilim 111:10). It gives grace to those who have it. Hearts love him, and people look to him with admiration.
Malbim: Sechel is the power in man to grow wise and penetrate in every matter with a sudden knowledge and judge matters hidden from the powers of Chachmah and Binah, even things that the senses have no approach to them, like knowledge of Hashem and intellectual beings. Sechel Tov is one who understands via Ru'ach ha'Kodesh. It is above human Sechel, which sometimes goes on a crooked path. If he has help from above, he truly understands everything via Ru'ach Hashem. It can come as Chaninah 1 . However, one who first had Sechel Tov and sees via Ru'ach ha'Kodesh based on his preparation, then Yiten Chen. It is not a Metzi'ah; it is given - "Yedaticha v'Shem v'Gam Matzasa Chen b'Einai", "va'Yomar Har'eini Na Es Kevodecha" (Shemos 33:12, 18). One who has Sechel Tov and understands with Ru'ach ha'Kodesh, also he drinks from a source of life, and Hashem will give to him Chen to know to veer from fatal pitfalls. It is as if it says Toras Chacham Mekor Chayim, and Sechel Tov Yiten Chen, Lasur mi'Mokeshei Maves.
Malbim: This Sechel usually comes as Chaninah (a free gift) for one who found grace in Hashem's eyes - "u'Matza Chen v'Sechel Tov b'Einei Elokim v'Adam" (3:4). It is called a Metzi'ah (found object), for it comes from above for one who found grace.
How is "Derech Bogedim Eisan"?
Rashi: It is difficult for him and for others.
R. Yonah #1: They make fraudulent claims, and delve deeply to support them with excuses and force the listeners to believe their claims.
R. Yonah #2: Their honor and elevation are only via power and instilling fear, or because people fear their power and might, or the honor of their wealth, and flatter them and feign honor. The heart of those who honor them does not admit to their honor. Eisan is a noun, as in "va'Teshev b'Eisan Kashto" (Bereishis 49:24). The Targum of "l'Eisano" (Shemos 14:27) is l'Sokefei.
Malbim: Those who betray Hashem and go in the way of death, their path is Eisan - a hard place that will not be worked or seeded, whether in a valley 1 or in mighty mountains, rocks that do not have on them earth proper for planting. They do not drink from Mayim of life, for they are not proper to receive water of dew or rain. So traitors are not proper to receive from a source of life.
I.e. "Nachal Eisan" (Devarim 21:4). (PF)