^^^ Agree with Hank.. Much easier to remove with both fenders attached..
But, if you only remove the front bumper, the Toyota lubricant is amazing stuff. It is better than PBlaster on rusty bolts.
If you do break off some bolts, dont worry!! I broke over half of my bolts. After you remove the bumper, spray the broken bolts with lubricate and then remove the bolts bolts on the back side using vise grip pliers. They usually come out easier. Replace them with Stainless Steel bolts.