I have always been tempted to try this.
3M spray on clear bra.
Amazon.com: 3M 90000 Paint Defender Spray Film: Automotive
Everything I have read says prep has to be perfect. Not even finger oil is allowed on the surface you are going to apply to. The masking has to be nice and crisp and also advice on the various forums say to use base masking tape, and then put a 2nd layer of masking tape for quick easy peel off.
Also people say you have to buy the spray on handle attachmemt.
Your mileage may vary.
After owning a Subaru for 10 years, a tom of miles (200k+) the areas worse were:
Hood leading edge up to 6inch up and then the roof from windshield to 3inch up.
Of course a truck is shape differently, but I noticed the plastic bumpers and mirrors were perfectly fine. I drove my Subaru through 10 winters in toronto where lots of sand and salt was used. The headlights were completely destroyed... Yellowed, scratched, hazed.... I used those head light restorer kits when the car was 8 years old... It worked for a summer and when wonder hit it got bad again .
I wouldn't waste your money on covering the plastic bumper covers or the side mirrors. Typically the hood (partial) + front bumper cover on a car is over 1000$.
I would hope a small strip on the front hood and roof is less than 200$.
When I get my new 4runner I plan on adding a sheet onto the back 1/2 of the roof where the racks are. I scratched up my Subaru over the years loading and unloading mountain bikes all the time.
If price is right I would do a strip on the hood edge and roof edge.
Just remember when you remove it the paint will have faded differently for areas protected vs unprotected.