What exactly was Moshe referring to when he told Yisro about "all that Hashem did to Par'oh and Egypt ... "?
Seforno: He was referring to Hashem's revenge against the Egyptians 1 due to the pain they had caused Yisrael - with reference to the Makos 2 that they suffered at the Yam-Suf. 3
Targum Onkelos and Targum Yonasan: He was referrin literally to everything that Hashem had done to Par'oh and the Egyptians concerning K'lal Yisrael.
As the Torah writes in Devarim, 32:41 (Seforno).
As the Torah describes in Tehilim, 78:49 - "Yeshalach bam Charon Apo; Evrah va'Za'am, ve'Tzarah, Mishlachas Mal'achei Ra'im" (Seforno).
Through which He indicated that He had chosen Yisrael as a treasure from all the nations (Seforno).
In the opening Pasuk in the Parshah, Yisro heard about what Hashem had done on behalf of Moshe and Yisrael. Why, here does Moshe mention Yisrael and omit mention of himself?
Oznayim la'Torah: Anybody else with the achievements of Moshe Rabeinu, would certainly have made sure to mention himself - but not Moshe, the 'Anav mi'Kol Adam'.
What exactly was Moshe referring to when he told Yisro about "all the travail that befell them on the way, and that Hashem saved them"?
Rashi: He was referring to the troubles of the Yam-Suf and the battle with Amalek. "All the travail that befell them on the way includes Milchemes Amalek and "all that Hashem did to Par'oh and Egypt ... ", Keri'as Yam-Suf - the two things that Yisro heard initially that prompted him to come out to the desert in the first place.; and now Moshe related to himj the details.
Rashbam: He was referring to Par'oh chasing after Yisrael and the water, the Manna and the meat with which Hashem provided Yisrael.
Seforno: He was referring to the hunger and thirst from which He saved them and from the pursuing army of Par'oh from which He rescued them.
Targum Yonasan: He was referring to the troubles of the Yam-Suf, Marah and Refidim (the water), and how He had saved them from the attack of Amalek.
Why did Moshe see fit to tell Yisro about the miracles that Hashem had performed with Yisrael?
Rashi: To attract him and bring him close to Torah.
Seforno: Refer to 18:8:2:3***.
Bearing in mind the obligation to offer an out-of-town guest something to eat (Bava Kama, 92a), why did Moshe first tell Yisro all that Hashem had done before offering him food?
Oznayim la'Torah (on Pasuk 7): Because every portion of Man was measured - an Omer per person, and there was nothing extra with which to feed guests. Moreover, it was forbidden to feed Nochrim Man, and it was only after a portion of Man fell for Yisro 1 - after he had circumcised and converted, that they were able to serve him a meal.
See Oznayim la'Torah, DH 'Vayavo'u ha'Ohelah' #2.