JasonJo
I am sure you have your reasons for posing the question but I think you are being a little paranoid. There is really no place in Philippines that is completely malaria free. If you are concerned just use off lotion and keep a stock of 'katol' to burn at night and also a plug in repellant.(all readily avail in Phils)
Avoid densely wooden areas and keep your legs and arms covered in the evenings.
Thailand and Laos have a much more virilent form of mosquito. For me the the mosquitoes here are less of a problem than the menacing little Scottish midges that used to attack me during the 7 days of summer weather that UK has each year
As for trips in Luzon. As other posts
Tagaytay, Cavite(island cove perhaps esp if like fishing) Nasugbu in Batangas,Splash mountain in Laguna(hot springs)
Subic bay,Iba Zambales then up to hundred islands and Lingayen gulf
San Fabian,Pangasinan, Manoag sidetrip,Buang,La union then north to Vigan or up the hill to Baguio
