Trees, Thanks for the great update and glad your alright. I drove some of those hills and know the turns are tight and the hills are steep.
Another check on the bolts with fatigue is the working bolt. With the fatugue the bolt can loosen due to minature vibrations and sometimes start the hole to elongate. If the bolts have been worked for a long time, a measure check on the hole is needed and the hole may need sized to the next size bolt.