Thought I'd show this. The red line on the picture - we called it "Rape Alley". I don't know when it got that name. It was used a lot to walk/cycle to the centre of York or back, basically the main route aside from a vehicle.
The spot I believe is where a rucksack was spotted. We would walk from Rape Alley right through this spot and down, turn left through Wentworth Way to get to Goodricke College. If you're coming from Green Dykes Ln, where I guess Claudia would be coming from, you'd also probably take this route. You can also stay on University rd from that direction and turn right on the roundabout, go through the main part of the campus and over the lake, but that's a longer way it felt like to me.
The purple line is a path through cow fields people took, not as common, but often enough. You can go throigh allotments or army barracks and end up very close to the police station, a quick shortcut to that part of the city.
The sighting of the couple arguing was on University Rd but I'm not sure exactly where?