I know how you feel. Not a hill in sight.
Last Sunday, to give the legs a taste of what's to come I did
15x reverse lunge each side
15 x squat press
15 x step up each side
90s rest
repeated 8 times in 40 min, all with a 9kg DB in each hand
That and a 20min 5k the next day finished off the legs
I might go and do reps of the cathedral precinct in Ely at the weekend just for fun
I used to commute by from home in Cambridge to work at Ely Hospital one or two days a week, so took folding bike on train, and had uphill ride from railway station to Cathedral. I also worked about 5 days per month at Wandlebury Country Park, so that involved 7 miles round trip bike ride with uphill to work on summit of Gog Magog Hills,then lots of foot patrolling. Not hills in the Yorkshire / Cumbria sense of the word, of course.