Skipper is good, Plaza is casual and decent, I still always love Liberty Tree as a long-standing tradition and easy plentiful comfort food - Diamond Horseshoe might actually be a better choice for a solo as Liberty Tree is more stuffed with families and big groups - Diamond serves the exact same food but in a smaller space and almost always available. I never worry about feeling uncomfortable solo at Disney - I've eaten at high-end prix-fixe down to bar food and seating, and never felt out of place there. I go where I want to eat the food.