1. Get greater hat of disguise
2. Alter self into a Sasquatch: medium, charu-ka: small
3. ????
4. Profit.
Also, come and get me is totally worth it. Keep it.
If I were building Sabretooth as a barbarian/ranger, I'd probably go with the Scarred Rager or Wild Rager for barbarian levels and the Shapeshifter or Wild Stalker archetype for ranger. Wild Stalker would be nice because it gives him back some of the barbarian class features he'd lose with those particular archetypes, and the rage stuff should stack with his barbarian levels at ranger level - 3.
I think he works better as a straight barbarian, personally - four skill points per level is enough to get him the outdoorsy skills he needs, and a lot of the ranger stuff doesn't fit him that well. Favored Enemy (Humans) would fit, though. I'd go half-orc for the race.
Natural weapons are a must - you can pick those up with Animal Fury and Lesser Beast Totem rage powers, or a half-orc racial trait for the bite attack.
If you do go half orc you can pick up the Keen Scent Feat. That should have you covered.
No, you just get the best one, unless you have a generous GM. With natural attacks you'll want an amulet of mighty fists, and maybe look into eldritch claws.