When I was 61 and my London Freedom Pass was a year old I travelled by bus from Lands End to John O Groats. I camped all the time as I had a popup tent on my back (like a snail). I had a roller suitcase which mainly contained bedding - it was the end of May!
I strayed into Wales and had to Pay £1.85 for a day pass! And, of course, I had to pay in Scotland. I thoroughly enjoyed the journey and saw many interesting and beautiful places.
15 years on, and in good health, I am thinking about doing it again! Problems - loos at bus stations, some bus routes not that near campsites, and charging 'my phone (don't think that one should be a problem now).