Owner is camping for the weekend and wants me to "drop in" once per day (Mid friday, Mid saturday and Sunday Morning) they come back Sunday afternoon. I suggested 2x per day for a drop in and the owner denied it. What should I do?

Have you asked if anyone else will be taking care of the dog, like taking it out first thing in the morning and in the evenings (like before/after work)? Also, have you described what a drop-in entails and what happens if you find their home a mess from the dog urinating or pooping indoors?