Is it permissible to combine and shorten prayers at a university that is 70 km away directly, and 85 km by bus, given the limited time for prayers?

If the bus takes the longer of two routes for a valid reason, such as ease of travel or picking up passengers, then it is permissible to avail oneself of the concessions for travel if the distance between the two ends of the towns is approximately 83 km. However, if the deviation in the road is due to unnecessary meandering right and left without an increase in the actual travel distance between the two cities, then it is not permissible to avail oneself of the concessions. It is preferable to shorten the four-rak'ah prayers to two rak'ahs if you do not pray behind an imam who prays in full. It is also permissible to combine the prayers (Dhuhr and Asr, and Maghrib and Isha) either by performing the earlier prayer at the time of the later or vice-versa, whichever is more convenient.