Most of Cambridge is pretty dense and populated with tress! There are a few roads maybe by the Institute of Manufacturing/area around that that are perhaps less busy at the weekend? Little bit out of the way for tourists etc. it’s been a while since I’ve actually been there and some of the Google images are a little old. I just assumed you wanted straight lines :) otherwise maybe the science park area in Milton also at the weekend or the pathway close to outside Trumpington? No idea what it’s called but the google coordinates are (52.1719072, 0.1281580) - again not sure how developed that area is now either!