Several hours of walking hadn't gotten her very far from the place she was escaping. Malfoy likely was made aware of her entering the Welsh village from someone who'd seen her get on a bus in Edinburgh. It wouldn't take much effort at that point to track down her final destination. As much as she might try, she wasn't always the most inconspicuous of travelers. If he knew she entered the village on a bus, he would probably assume that she would leave that way too. Avoiding all Muggle transportation for awhile would be a safe bet.