2nd is fine if you need it, like on steep downhill secondary roads. It is doubtful that you would encounter an interstate downhill grade that was so steep you would need to use 2nd gear, nor would you want to slow down that much on the freeway for fear of being rear-ended. I use 2nd a lot in the twisty, hilly roads around Northern Calif. I have to use first on some of the very steep streets in my neighborhood to save my brakes excessive wear, but I go pretty slow when I do that. Just watch your tach to ensure engine speed stays below 3500-4000 max, and if you are moving significantly slower than the flow of traffic make sure you put your flashers on like truckers do.
The others are correct about using the brakes periodically to bring your speed down, then letting it slowly build back up and giving them time to cool briefly before applying them again, rather than riding them constantly. Be careful about pulling off and stopping to let them cool. They do not get nearly as much airflow just sitting there stopped and you can even warp a rotor where it is sitting stationary in the caliper between the pads. Better to keep it moving and cool them down as the road levels off.
2012 Flying Cloud 23-D
1971 Safari 23 (sold)