The Mayacamas Range is laden with some pretty gnarly roads. Hair-pin turns, narrow, gravelly roads, cliff edges - it’s a challenge for even the savviest of drivers. You will want to give yourself PLENTY of time to get up there if you want to arrive on time with your breakfast still in your stomach. Definitely hire a driver if you don’t plan on spitting, you will not want to navigate that road with even 1 glass of wine in your system. Also, because service is spotty don’t rely upon uber to come pick you up and it is illegal for them to wait for you.
Howell Mountain and the rest of the Vaca Range is slightly more civilized than the Mayacamas Range, but you should still proceed with caution.