For interisland, I always fly HA (new 717s) and simply pay the $80 or so (i can't remember how much). If I had some OW miles, I might use miles for the HA interislands, but I'd rather just pay, they aren't real expensive (relatively, yes, they're expensive;BNA-FLL for $83, but $80 isn't much).

my (kind of confusing) 2¢

bottom line, I prefer to just pay for an HA interisland on the 717s (I'm *A and SkyTeam, no HA miles available)