Guys, how would you break up 16 nights West Coast (arrive LAX 11th, depart LAX 27th)
1 x LA
2 x SD
3 x LV (inc GC)
3 x DV and YNP
2 x SF
2 x Monty and PCH
1 x SM
Gives an extra night or two somewhere..
Ta
Let's see if I can help - I live in LA, but from the UK originally and do this kind of trip 3/4 times a year for various bits of work and when friends come to visit from the UK. Here would be my advice and musings:
LA - I personally love LA, but I know many don't. You can hit up most of the tourist bits in a few hours, and they get dull pretty quickly. LA really gets exciting when you have time to explore and get out of the tourist hotspots. If you get a chance, just head to downtown LA - A bunch of great bars, restaurants and hidden gems. Always my favourite place to be in LA.
SD - I'm not a fan of San diego. I'm there every couple of weeks as the misses family live there. I would spend a couple of hours there and then hop the border to Tijuana. It's really not nearly as bad as people would have you believe and is far more exciting that SD. If you have a chance hit the zoo in SD, but it will take a good part of the day. Aside from this, 2 days is too long - you'll just spend your time in crab shacks watching the beach.
LV - You could hit Palm Springs on the way to LV as others have suggested, but I really wouldn't bother. Palm Springs is a great place to go and relax, and 95% of the people you will meet there have come from LA to real for a couple of days. If it helps put it in to perspective - We have a house in Palm springs, and we still barely go. For Las Vegas, 3 nights is about the limit for most people. I would suggest cutting it down to two nights, you'll get everything you want in as a tourist (try and do this during the week to save cash on hotels). Use the extra day elsewhere.
DV and YNP - Yosemite, is by far the most beautiful place you can visit in California. I would recommend spending as many of your days here as possible. If you can, money saved form the extra night in Vegas, put towards renting a tent a try to camp there for a couple of days. Get some hikes in, and enjoy not driving for a couple of days. As mentioned, hotels around here are few and far between, and the ones that are charge a fortune. On the way as well, you might as well hit Mammoth Lakes, gorgeous views.
SF - SF is also one of the greatest parts of California. I would try and increase this to 3 days if you can. So much to see and do, and just a great city to get lost in.
M and PCH - Monterey is a great place to spend a few hours. Have a look to see if anything is going on at Laguna Seca. One the way down, visit Carmel for a quick stop (beautiful little town vibe - Clint Eastwood used to be mayor there - his claim to fame as mayor there, was that they were trying to pass a law there to ban ice cream, as all the ice cream drips from the cones were staining the pavements there. Clint Eastwood laughed, ripped it up and enjoyed an ice cream. So go have an ice cream in his honor. Is you do one thing on the way back - Visit Big Sur. Another one of the most amazing places in California. You will hit it on the way down the PCH - but don't rush through it. visit some of the beaches, eat there (A restaurant called Nepenthe is an absolute must for the views). Also on the way back down, don't rush to get back to SM. Visit San Luis Obispo on the way back, hit santa barabara.
SM - Sack this idea off. Santa Monica gets old in about 5 minutes. I opened an office in SM, very quickly relocated it. Go to Malibu on the way down instead (the beaches are far nicer, less crowded - and almost every time I go there, we see Whales and Dolphins meters out in the ocean, pretty awesome), and if you have time - skipped past Santa Monica and go 5 minutes down the road to Venice. Or if that doesn't appeal, go to Manhatten Beach (Don't get in the water - A swimmer was bit by a great white shark last week!), or head down to Long Beach.
There are a LOT of fun little towns and places to visit in between, but for a two week trip, you won't be able to get them all in. Once you have a solid plan in place, email me or something, and I will go in to much more detail for you.
Also - with regards to Hotels. My advice would be to book nothing. Over here, we all use an all called Hotel Tonight. Whenever we go away, we use the app on the day of, and get most of our hotels around 40-50% off. I wouldn't use anything else.