There are several ways to travel to Naresuan University from Bangkok. You can easily come by bus which departs from Bangkok almost every hour. Otherwise airplane is also available daily as the detail shown below.
1. By Airplane (45 minutes from BKK to Phitsanulok)
Free Shuttle Bus transfer Suvarnabhumi - Don Muaeng
Service time 05:00 a.m. – Midnight (every hour depart)
Platform of Suvarnabhumi Airport Passenger: Terminal 2nd Floor, Gate 3
Platform of Don Muaeng Airport passengers: terminal 4th Floor, Gate 5
2. By Bus (5 – 6 hours from BKK to Phitsanulok)
You can click the following websites of bus for your travel options.