Last week, when the blog on the Bluff Wilderness Trail was posted, I promised to share the lessons I learned on this backpacking trip. They may not look like big mistakes, but together or even separately, they could cause big headaches or worse.  Full disclosure: I ‘m a bit embarrassed to admit them, but here they are.   I cheaped out on a sleeping bag.  I have a good sleeping bag, but it’s big and heavy.I wanted one small and light for backpacking-and I got it. It was plenty roomy-I checked that out beforehand. But it’s kinda hard to gauge a sleeping bag’s warmth from the comfort of one’s…