Accessing the walkway to the front door and knocking on the front door is not trespassing, even if there is signs posted. Wandering off the path, going around the back, looking in windows is trespassing - but accessing the front door to deliver, ask for directions, or invite someone to tea is not. You can be asked to leave which then could be turned into trespassing. Decent write up about it - https://www.radford.edu/content/cj-bulletin/home/june--2017-...