I meet my guests and walk through the space. i would in this case have already told the guest exactly where to park (we actually do tell them that) and also would have briefly verbalized the house rules and location of the various amenities.
If you can't/don't want to meet them and check them in then you could put up a sign letting them know that there is no parking in the driveway. You could get a sign that you turn around for the guests that can park and turn back for the guests that cannot.
For the front door, put a sign on the inside that says {Please lock door when leaving} and point it out to the guests during check in.
The guest is not used to living in your home and is fumbling around cluelessly. They need clear direction.