You recognize you are pushing your limits, you need to drive accordingly and be aware of what is happening around you. When climbing keep your speed down to avoid overheating, turn on your hazards if going appreciably slower than the rest of the traffic and stay in the right lane. On two lane use turnouts to allow traffic to go by and smile at the salutes you will inevitably receive.
Downgrades require special consideration. Slow at he top and use the tow/haul. On steep grades drop a gear and again use the hazards to warn drivers behind you, if speed starts to climb snub the brakes firmly then get off the pedal. DON'T ride or pump them. Also, consult the map and plan fuel stops, they will be frequent.