Wait for a reply from the experts, as I did these a LONG time ago, but Three Shires is a beauty, a joy of a route, and MUCH more interesting than Langdale. You are right about the descent off Blisco, tho there's a well trodden path now. Up Lingmoor is easy, down is tricky. Even the stars go wrong sometimes. But you can't go hopelessly wrong by that stage, and even the wrong route choice will only mean a matter of minutes (which matters, of course, if you are at the sharp end of the field!) But you will have a great day out, and you will have a warm welcome in Little Langdale.