My family is from Isabela and the last time I travelled from Isabela to Manila was 2003 and it took me 9 hrs. I used a nissan pick up and took 3 stop overs. From our place to Tuguegarao is about 2 1/2 hrs using not the maharlika highway but the new route which passes thru Aurora, Roxas, Kalinga Apayao, Enrile then Tuguegarao. With the traffic situation along Bulacan and Nueva Ecija, travel time could be at least 10 hrs with 2 stop overs. Baguio is about 6 to 7 hrs from our place using the Sn. Jose Pangasinan route, if you are coming from Cagayan add 2 more hrs, if you are going to use the Cagayan - Ilocos - La Union route it could be longer by 3 to 4 hrs. To reach Tuguegarao in 6 hrs, you have to drive at constant speed of at least 80kph non stop.