Variety of places. Sometimes just drove through nice neighborhoods and asked a homeowner who happened to be working in the yard if we could park in front of their house for a few days. Once called up the local police and asked for suggestions - they said we could park in the police station lot. Another town had a section of their downtown garage available for longer term parking. Another trip started in a national park and the rangers said the lot by the park store would be fine for several days.
Never encountered any problems.