Start with this Du'a
Entering a town or city
اللَّهُمَّ رَبَّ السَّمَاوَاتِ السَّبْعِ وَمَا أَظْلَلْنَ، وَرَبَّ الْأَرَضِينَ السَّبْعِ وَمَا أَقْلَلْنَ، وَرَبَّ الشَّيَاطِينِ وَمَا أَضْلَلْنَ، وَرَبَّ الرِّيَاحِ وَمَا ذَرَيْنَ، أَسْأَلُكَ خَيْرَ هَذِهِ الْقَرْيَةِ وَخَيْرَ أَهْلِهَا وَخَيْرَ مَا فِيهَا، وَأَعُوذُ بِكَ مِنْ شَرِّهَا وَشَرِّ أَهْلِهَا وَشَرِّ مَا فِيهَا
Allahumma Rabba-s-samawati-s-sab'i wa ma adhlaln, wa Rabba-l-aradina-s-sab'i wa ma aqlaln, wa Rabba-sh-shayatini wa ma adlaln, wa Rabba-r-riyahi wa ma dharayn, as'aluka khayra hadhihi-l-qaryati wa khayra ahliha wa khayra ma fiha, wa a'udhu bika min sharriha wa sharri ahliha wa sharri ma fiha.
“O Allah, Lord of the seven heavens and all they shade, Lord of the seven earths and all they carry, Lord of the devils and all they lead astray, Lord of the winds and all they scatter. I ask You for the good of this town, the good of its people, and the good of what is in it; and I seek refuge in You from its evil, the evil of its people, and the evil of what is in it.”
Sahih Ibn Khuzaymah 2565, Sunan an-Nasa'i al-Kubra 10302 (hasan) · Graded sahih by al-Albani, as-Sahihah 2759
Said upon sighting or entering a town on the journey.