The closure at Lucia will probably be lifted by Sept. but you'd still have to take the Nacimiento Fergusson Road, which, as mentioned, is not for the faint hearted.
Breaking news. The closure near Lucia, called Paul's Slide, will open today, July 18. It will be one way, controlled traffic, open 24/7. That means only one lane will be open, and north-and south-bound traffic wil alternate using it.
3days to drive south (Carmel/Monterey/Big Sur/Santa Barbara)
Much of "Big Sur" is simply off limits. You can drive as far south as Bixby Bridge to get a feel for it, but you'll have to drive back north and detour to US 101 to drive farther south. There is a section open, via the Nacimiento-Fergusson Road, but this is slow, narrow, and dangerous road, which may be closed at times for military exercises (it passes through a base) or to allow construction equipment through (to repair Highway 1).
Will this detour add long stretches of non interesting driving to our route?
I was aware of the closures but have read a lot of mixed information about the re-routed version while still seeing as much coastline as we can.
Re: Yosemite lodging we haven't booked yet as the trip was just decided on last week!
I know this is late notice and we aren't likely to get accomodation in the park and so thinking of something close to Big Oak Flat entrance as I think this is the direction we will approach from SF.
Any reccomdations here?
We also aren't against camping but I haven't found many places we can rent tents etc and bringing our own on transatlantic flights for just a few nights seems silly/extreme!
Re: Hostels. There are also several hostels along the coast south of San Francisco near Half Moon Bay, in converted lighthouse buildings. These are really wonderful properties, literally right on the water. I stayed in the one at Point Montera, we got a private room with ocean view for $60/night - this was 10 years ago now so rates are higher now, but still. A room like that in a conventional hotel would be many hundreds of $$ per night. The one at Pigeon Point also looked nice, but was full at the time of our visit.
I'd at least consider hermosajoe's recommended partial coastal/partial inland route. If you're from Ireland and have traveled coastal regions elsewhere, you have seen much beautiful coastline. Big Sur is great, but its not so much better than other famous coasts, or even other regions of California...not 100% sure that at this point, with the little time you have, that it is worth all the monkeying around with long detours and back-tracking. The route suggested in #6 takes in part of the coast, then turns inland for a tour of the high Sierra before heading back to the coast at LA. I promise you have not seen terrain like the eastern Sierra Nevada. I might tweak it a little like so:
3 Nights SF
2 Nights - Monterery/Carmel
2 Nights Yosemite
2 Nights - Mammoth Lakes/Bishop/Lone Pine (eastern Sierra on 395)
4 Nights LA
If you could come up with an extra night, it might be nice to have 3 in Yosemite.
Here's another option for you, get campervan for the road trip part. Takes care of lodging issues. If your considering only part of the coast it could work.
What are your dates in September for this trip.
You could camp in Pfeiffer Big Sur State Park, lots of openings in September. Probably because of the detours, very surprising. Weekends could be a challenge but looked doable.
https://www.reserveamerica.com/camping/pfeiffer-big-sur-sp/r/campgroundDetails.do?contractCode=CA&parkId=120068
For Yosemite you could camp in White Wolf, first come campground, and drive to the Valley. pretty easy if you get there before noon especially on a weekday.
For Lee Vining, Mammoth Lakes or Tom's Place there is great camping all over, no worries.
You could go with 2 nights each place. A campervan is perfect for 2 people and includes the camping gear. It ain't your rag top Mustang but act like a hippie and you'll get by plus you'll save some money.
Turn the campervan in when arriving LA and get a cheap car.
http://www.escapecampervans.com/
https://www.jucyusa.com/
http://lostcampersusa.com
Will this detour add long stretches of non interesting driving to our route?
It's not terrible, but not as scenic as the coast.
In the event you decide to stick to the coast, drop into Pinnacles NP. I doubt you have that back home either.
That's a great idea, will def look into this.
Are they difficult to drive though or just like a car?