Any reasonably fit person could pedal 50 miles a day, here's my bike in mid-Wales during one cycle-campng trip, I left the coast near Aberystwyth and crossed the width of Wales from west to east into England in one day (60 miles).
The great thing about cycling is that the back wheel takes all the weight not your legs! My saddlebag is crammed with a sleeping bag, and my small tent and food bag are lashed on top, and I've thrown an orange waterproof cagoule over the whole caboodle.
The trick with cycling is to NEVER PUSH THE PACE. Take regular food 'nibble' breaks sitting against farm gates; walk up all hills and you can go on forever.
Longest I ever did in one day was 145 miles from Kent to Leicester but I had a following wind and good summer weather..






