New Jersey reply here:
My son has a 2002 Tacoma double cab that still had a decent amount of Noxudol 300 on it from the Toyota voluntary recall. We simply washed and reapplied over the entire frame. Not wanting to apply a different product over the top of it. We used Noxudol 700 cavity wax inside of the frame rails as well.
When my 04 tacoma got a new frame, I chose to treat it using the cavity wax (above) on the inside of the rails and this product RP342:
Cosmoline Vehicle Undercoatings - Long Lasting Rust Protection for Vehicles everywhere else on the frame and underside of the body.
So far each is holding up ok, occasional touch-ups as needed. As was suggested in comment above. A self healing product is best.