Why did he say that Tov and Chesed will pursue him?
Radak: I thank You for the good that You gave to me until now - but I request that Your Tov and Chesed pursue me my entire life, and I not be distracted with wars and worldly engagements.
Malbim #1: You took me from isolation to kingship, Bal Korchi (against my will). May Tov and Chesed pursue me, that I will flee from royal wealth.
Malbim #2: Now I see that this that enemies pursued me my entire life, was only Tov and Chesed. Through this I reached kingship, and still I sit in Beis Hashem, and do not abandon His Avodah and fear!
Agra d'Pirka (238): David prayed that he will have only Tov; evil will be Batel from him. Then Chesed will pursue him. If he has Ra, Hashem will summons Gevurah to get angry at a matter of Torah, in order to burn the evil.
What is "Shivti b'Veis Hashem"?
Radak #1: It is ability to be isolated there, and prepare my heart for Your Avodah and unity. It is an expression of [serenity, like] "b'Shuvah va'Nachas" (Yeshayah 30:15).
Radak #2: It is going there constantly, day after day. Beis Hashem is the place of the Aron (the Mikdash was not built yet).
Malbim: Even though You brought me to kingship, may I always live in Beis Hashem like a Nazir (separated from worldly pleasures).
What is "l'Orech Yamim"?
