Myself and 2 friends bought some cheap bikepacking bags, way overpacked, and decided to follow National Cycle Route 3 from Bristol to Bude and back over 4 days (roughly 380 miles). It was a bit of a disaster, but we had fun nonetheless. It turns out that blindly following a national cycle route in the UK isn't the best of ideas. Well some of the terrain was suitable for our road bikes, there were other parts where a hardtail mtb would have been better. So we did a lot a re-routing on the fly. And also realised 90-100 miles/day fully loaded was a bad idea. We were riding for like 12 hours a day, and not really getting to enjoy the trip and the scenery. We do a bit more planning nowadays, ride far less miles, and still have a ball. We still sometimes overpack though- though I have gotten my set-up (including bike) to around 17.5-18kgs for up to a week's camping.