We will be visiting California from the UK next April and as part of our trip are planning a journey from Cayucos across to Yosemite. Is this a realistic journey for one day? What route would you recommend? What alternatives might there be? What stopping off points?
Any advice appreciated.
RogandLin

Definitely doable in 1 day. It should probably take about 5 hours or so to make the drive, not including stops. There aren't a whole lot of things to see along the way, mostly just farm land. I haven't driven this route entirely, but it looks like you can head right up Hwy 41, which will ultimately take you into Yosemite through the south entrance. This will be a great way to enter the valley because you go past the Tunnel View, which is an exellent vista point just after you come out of a tunnel through the mountain. From this point you can see Half Dome, El Capitan, Bridal Veil Fall, Clouds Rest - basically the whole valley all in one view.

An alternative to the route suggested by J_Correa (which is the shortest route) would be to turn north on CA-49 at Oakhurst, go north to Mariposa, then enter Yosemite on CA-140. This will be a few miles longer than the other route but CA-49 is scenic and Mariposa is a fun little gold-rush town to spend an hour or two exploring.

Are you planning on going to Yosemite and driving back to Cayucos in ONE DAY? If so, that's a LOT of driving and won't give you much time in the park.

Utahtea

Most locals would probably head north from Cayucos a few miles and then take hwy 46 going east from the coast, shifting to hwy 41 after they join to head through Fresno to Yosemite. The western section of hwy 41 is rather slow and twisty. 5 hours plus stops sounds about right for travel time.

There are a number of wineries around Paso Robles, then a lot of dry and empty terrain, then the central valley farming areas. There are places for gas and food along the way, but not much else. Buy gas in Mariposa before heading up into Yosemite.

Thanks for all the replys, it's a real help. We are planning to travel one way and spend a few days in Yosemite. What about the journey from Yosemite to Tahoe? Can that drive be done in a day? We will be travelling mid April and were wondering about any problems with the weather.

Snow is a definite possibility in April, both in Yosemite and at Tahoe. We were in Yosemite this year in mid-April, and while there was no snow in Yosemite Valley, we had about 8 inches fall on the highway 41 and 120 routes while we were there (I think it was just rain on hwy 140). At that time of year, the roads are usually clear and dry within a day or so after a storm, but there is a chance that tire chains will be required. The same applies to Lake Tahoe (most Tahoe ski resorts close in mid-April due to lack of skiers, not lack of snow).

April is usually good weather, but you do need to be prepared. It helps if you don't have a rigid schedule, so you can adjust your travel days if a storm passes through. If you plan to go to both Tahoe and Yosemite, you should probably have chains for the car, though you probably won't need them (beware that not all rental cars can use chains).

It is a longish drive from Yosemite to Tahoe because you have to drive down out of the mountains and then back up again. With good weather, I would think about 5 hours, depending on your route.