make sure your kit is up to scratch
I bought and rode home from Redruth in Cornwall to Liverpool....355 miles in a day. Coz I travelled down on train, I never took/wore my gear but layered up in civvy clobber.....big mistake
foccing freezing over Bodmin moor, pissed down to Brum with snow/hail chucked in for good measure....only weather I never had was sun!!
I took a flask and had regular tea/fuel stops but was hypothermic (literally) by time I got home
this will fook you up especially if you get lost so jot down the route as others have said but wear the right kit
good luck