One option is the Magilas Trail via Rosales, Sta. Maria, Asingan and back to MacArthur Highway at Binalonan. This bypasses the traffic in Villasis and Urdaneta City.
But another option is to take an alternate route from the Tarlac City SCTEx Exit itself. Instead of making a left back to MacArthur Highway, I made a right and took the alternate route to Baguio via La Paz, Victoria, Guimba, Cuyapo connecting to the Magilas Trail in Rosales. This skips traffic along MacArthur Highway from Tarlac City all the way to Binalonan, Pangasinan.
It's a bit longer but faster. Roads are relatively good plus vehicles are scarce. So there's less stress driving since I didn't have to worry about driving in crawling traffic or overtaking slow vehicles except for the occasional tricycles which occur much, much less than along MacArthur Highway. Travel time from the Tarlac City SCTEx Exit to MacArthur Highyway in Binalonan (97.4 kilometers total) via this alternate route is under two hours.
What's good about the route is that it's clearly marked by directional signs both ways. On the way to Baguio, just make sure you pick the route via Guimba as you exit Victoria since the other option via Pura, Ramos and Paniqui will bring you back to MacArthur Highway and Urdaneta City traffic.
Remember though that this alternate route is good only for the day time when traffic is bad along MacArthur Highway. Also make sure you're gas tanks are full and that you've eaten or have supplies on board since there's nothing much along the way. In fact, you don't even pass by town propers except in Victoria, Tarlac and Rosales and Binalonan, Pangasinan.
Going up Baguio, Kennon Road is my choice during the day time and when it's not raining. It's shorter, faster and very scenic. I enjoy the view of its many waterfalls which become all the more evident after it rains.
Sadly, GI sheets started to mushroom all over the place. There are now two houses at the base of Bridal Veil Falls destroying the view. And Camp 6 in Tuba, Benguet is the most horrible! The local government of Tuba should start doing something to protect the wonderful view of this historic road.
Also remember that there is ongoing road rehabilitation in the Camp 8 segment. So Kennon Road is one way in that area. So going back down to Manila, you'll have to pass by Marcos Highway or enter Kennon Road via Loakan.
Waterfalls along Kennon Road