The drive up is amazing. It requires 4x4 as the trip DOWN is steep and the low gear has to be LOW gear. We drove up with a Jeep and had no issues....I took it slow as instructed, both up and down. There are no guardrails to speak of...a few here and there...the road starts tar, then immediately turns to dirt and starts to climb. Do not worry if there are low clouds, you drive above them....no worries. The accent takes a little while and if you go slowly as instructed, you accumulate to the altitude as you go. Same with down. GO SLOWLY.
The only thing I wish was some type of visitor center at the top. where are you allowed to go, where are you not? How about a tour of one of the telescopes? THAT would be AWESOME. How about offering Observatory BUS rides up...so everyone can go? Charge $10 for the ride up...and a professional drive. Anyway, the trip up was worth it. Remember it's the trip up more than what is up there...as once you arrive there are a LOT of HUGE buildings...a site on it's own. But that is IT....nothing to enter...nothing to see except the view....and even with the clouds below us, the view was spectacular. The ride down MUST be taken slowly....low gear in 4x4 low. 15-20 mph. Why hurry? You could end up sick due to altitude change and it is a dirt, gravel road that makes hairpin turns with no guardrails. NO ONE UNDER 16 IS ALLOWED to the summit!!! So those who brought young children didn't stop at the visitor center. Altitude sickness is real.