What is the ruling on shortening and combining prayers during a journey lasting four days and three nights?

It is permissible for the traveler to shorten the four-rak'ah prayers and to combine the prayers that share a time (Dhuhr and Asr, and Maghrib and Isha); and it is permissible for him to combine them even if he is not actively traveling, based on the hadith of Mu'adh in Sahih Muslim concerning the Battle of Tabuk, which indicates the permissibility of combining prayers for a traveler who has dismounted.