The idea of visitability is that anyone - those living on the property as well as those coming for a brief visit or longer-term stay - can enter and leave without encountering any challenges or obstacles. This means total freedom of movement by anyone, regardless of their physical ability or any mobility challenges they might have.
The whole idea of being able to visit a home successfully and easily - by those living in it full-time or those dropping by for a quick visit, those invited to an event, or those staying overnight or longer - is that they must be able to approach the home from the street and get to the front door, pass through the entry door, and then move about freely once inside. It extends through the home into the backyard also - for those occasions when the event is a cookout, siting and relaxing around a firepit or fireplace, a backyard party, a pool swim or spa party, or other outdoor activity.
None of this can happen when there are challenges along the way that hinder or prevent the freedom of access or movement from the street onward.
When people arrive by vehicle, it means that there is room for them park and get out of their car on a hear surface and not encounter landscaping, curbs, gravel, mulch, loose dirt, or other material that would create unsafe or uneven footing on which to step and walk. From there, it means a continuous hard surface walkway to the front door.
For those who are arriving on foot from adjacent homes in the neighborhood, or those who park on the street, the walk to the front door is longer than from the driveway but just as important. It needs to provide an uninterrupted safe path from the street to the driveway or all the way to the front door, depending on how it is designed.
Too many walkways consist of unattached stepping stones with gravel or grass between them broken pavement that is uneven, dirt or gravel pathways, or solid surface walkways with grass, weeds, sand, leaves, standing water, or other materials inhibiting safe footing.
Getting toward the front door is just the first phase of the visitability process. The landing area in front of the door - stoop or porch - is equally important. Ideally, there are no stairs or steps to negotiate to get to the solid surface landing, and the landing area is large enough to accommodate more than one person at a time. It needs to be large enough for anyone awaiting entrance to be able to stand - unaided or while using a walker or wheelchair - out of the way of the door opening out toward them (whether the entrance door or storm door).
The landing area needs to possess two other important qualities. It needs to be well light and covered. The lighting enhances the safety and security by illuminating the footing and making sure that there are no shadows that might suggest unsafe conditions on the approach to the porch or landing and while awaiting the door to be opened.
The covering is important - more than a typical overhang - because people want to arrive at the door and wait there in dry conditions. If it there is precipitation falling, and especially if it is blowing, people like to wait for entry without getting wet and then tracking that moisture inside with them.
Now, the door can open and people can enter. There is more to consider about visitability once inside, but these measures help put the "visit" into the process.