I could rather replace Return with Body Slam, Double Edge had already the enough power to destroy things, and Return is somewhat redundant (somewhat less power without recoil), while Body Slam still hurt things, and the paralize effect can help a lot to your team (as for the hax or the speed reduction).
Also, a good benchmark with the speed is 227, in that way you can speed any Leafeon and Murkrow without investment on speed (and max investment Beartic, Huntail, Gorebyss, and standar Semistoad), it can comes handy. Another decent benchmark is 234, for outspeed max inversion Ursaring, Relicanth, Amparos, and Torterrra (and max inversion with neutral nature Seviper, and standar Solrock). I don't think it's a good idea to invest more on speed than 234, you're losing too much bulky with it, and you're not outspeeding nothing important, maybe 243 for outspeed standar Skuntank, and max investment with neutral nature Ludicolo, Dragonair, Victreebel, Luxray, and Samurott. With more than 243 you're not winning absolute nothing apart from outspeeding the rare Electabuzz, so, it's the highest speed I could see ok on Kangaskhan.
Emboar's ascend to RU helped Kangaskhan, too, because it was a decent idea to archive 252 of speed to outspeed max investment Emboar, losing an important part of it's bulky just because him. Anyway, spend at least 4 EV's on speed to outspeed Golbat, Kangaskhan works really well without speed investment at all, anyway, because you're not outspeeding anything really important at all (Khan can take hits of all of them and heal itself with Drain Punch or just leave them without options with Double-Edge).