1. You almost have to read "re'eh es shlom achecha" as Ya'akov telling Yosef more than just to see how his brothers' were doing -- Ya'akov was telling him to view his brothers with an eye toward making shalom, toward avoiding stirring up their animosity.
2. The Midrash writes that had Reuvain known the Torah would praise his efforts to save Yosef, "Vayatzileihu m'yadam," he would have run with Yosef on his back and brought him home to his father.
Surely it was not the publicity, the praise of having his good deeds mentioned, that motivated Reuvain! If he thought Yosef should be saved, wouldn't Reuvain have made every effort to do so regardless of whether the Torah mentioned it or not? (Those who are regular readers may recall a hesber we said from the Lubliner Rav about a similar statement the Midrash makes about Aharon. When I wrote that post (link) I commented that I don't know how to fit his pilpul into the same Midrash about Reuvain... well, now I know, and so will you.)
Ksav Sofer explains that Reuvain actually had every reason to not want to bring Yosef home. Remember, it was Reuvain who was guilty of being "mebalbel yetzu'ei aviv," moving Ya'akov's bed from Bilhah's tent into Leah's (according to Rashi). What better way to diminish his own embarrassment at having done wrong than to have Yosef delivering gossip about his brothers shortcomings to his father. Even though in reality Reuvain's motivation was pure, the greater the effort Reuvain would have made to save Yosef, the greater the gossip would be that he only went the extra mile because of self-interest. Therefore, he restrained himself.
The pasuk in our parsha, "Vayatzileihu...," testifies that Reuvain in fact was motivated only by his desire to save Yosef and not by any selfish motives. "Had I know that the Torah itself would testify as to my motives," said Reuvain, "I would have grabbed Yosef and run home with him," as he would not have to be concerned with whispers behind his back.
Pilpul is geshmack, isn't it?
3. Since we are dealing with Reuvain, let me share with you a Yismach Moshe. The pasuk says that the brothers plotted to throw Yosef into a pit, "V'nireh mah ye'hiyu chalomosav," (37:20) and we will see what will be with his dreams. Rashi splits the pasuk into two parts: The brothers plotted, but it was a bas kol that declared from Heaven, "We will see what happens with those dreams. It's as if Hashem was saying kavyachol, "Let's see whose plot wins -- yours or mine."
The very next pasuk tells us, "Vayishma Reuvain vayatzileihu m'yadam," Reuvain heard and saved Yosef. What did he hear? The simple pshat is that Reuvain heard the brothers plan and wanted to thwart it. However, in light of the way Rashi explains the previous pasuk, the Yismach Moshe explains that it was the bas kol that Reuvain heard.
4. Reuvain tells his brothers to throw Yosef into a pit, and the Torah immediately again reminds us that Reuvain's plan was to save Yosef, "l'hashivo el aviv," to return him to his father (37:22). If Yosef is saved, doesn't it go without saying that he will be returned to his father?
The Radomsker explains that it's not Yosef the pasuk is talking about, but Reuvain -- Reuvain will be returned to his father. He doesn't say it, but I think it's fair to suggest that the pasuk means that Reuvain himself would be returned to the good graces of his father by saving Yosef. Note Rashi's comment to 37:29 -- Reuvain was engaged in doing teshuvah for that sin of bilbeil yetzuei aviv while all this was going on. But the Radomsker goes a step further: The father being spoken about in the pasuk is not Ya'akov, but rather it is our Father in heaven. Reuvain's mission was to return himself, his personality, to its former state of closeness to Hashem (see his explanation of why specifically Reuvain).
This vort sheds light on what the whole parsha of Yosef and his brothers can teach us. Yosef is that aspect within us that pulls us to tosefes kedusha, yet with every aliya, with every step upward, there are more faults of ours that we have to contend with. Rather than face the "dibasam ra," we try to quiet Yosef, maybe by tossing him in a pit somewhere where he cannot be heard. Reuvain's job is to come to the rescue, to return Yosef, and in doing so, to return himself to that state of closeness to Hashem.