EV train in Speed and Attack.
Kangaskhan's base 90 Speed is a gift, allowing it to out run some of the top threats in it's tier, such a Pinsir, Sawk, and Gardevoir. And on top of that, it can use Fake Out and break Sawk's Sturdy and KO.
Do Attack simply so it can hit hard, and why let a movepool like that filled with dangerous priority in Sucker Punch and Fake Out go to waste? And other than that deadly priority, it's movepool contains great moves like Double Edge, Eathquake, Drain Punch, Focus Punch, and more. Plus, it can pretty much spam Double Edge until a Steel or Rock type comes in.
Here's some movesets I recommend using.
Kangaskhan @ Life Orb / Silk Scarf
Trait: Scrappy
EVs: 252 Atk / 252 Spd / 4 Def
Adamant Nature
- Double-Edge / Return
- Drain Punch / Earthquake
- Fake Out
- Sucker Punch
Kangaskhan @ Choice Band
Trait: Scrappy
EVs: 252 Atk / 252 Spd / 4 Def
Jolly / Adamant Nature
- Double-Edge
- Sucker Punch
- Eathquake
- Drain Punch
Hope I helped! :)