It is sometimes said that the whole point of hobbits as protagonists, for Tolkein, was that they were never meant to go adventuring in the first place. They were weak, soft, sedentary creatures, with copious appetites and a great love for civilized niceties.
doesn't really fit into the standard model for OSR classes, where you
have a prime requisite, and for demihumans in ACKS at least also a
minimum stat in order to qualify for your race. However, rolling 3d6 in order does
occasionally generate a set of stats which is literally unplayable; the
simplest case would be something like a set where all stats were less
than 9, though it would also be possible to do with a high Con and
possibly a higher Cha, since there's no Cha-only class in Core.
And that's where hobbits should come from: the stat sets that don't qualify for any other class. Give them a racial maximum stats instead of minimum stats, and maybe an inverse prime req bonus, where the more horrible your stats are, the more XP you get. I'm only about half-joking.
don't really know what else to give them - probably not great fighting,
some sneaking, decent HD (they do not seem to die as often as one might
expect...), tendency towards ridiculous circumstances... But at the
end of the day, playing a hobbit should be less like playing a ranger
than playing a tourist who, despite his absolute unfitness for adventuring, makes do with a surfeit of either blind luck or divine providence.
Really good saves, I guess.