I went to Yosemite twice in 2010 (my son was working there) including once in April. A few things to consider:
1. In April, there will still be snow and Rt. 120 may require snow chains. In April 2010, it snowed after we were in the park and all routes out of Yosemite required chains. Rt. 140, which does NOT go up in elevation as you leave the part, was our only option the next day as the other routes (120 and 41 required chains).
2. The road from Rt. 49 to Groveland is VERY curvy! Even the Yosemite Pines website recommends that you take an alternate route:
Directions from Southern California:
RV'ers, please do not take Hwy 49 as Mapquest recommends, road is very windy and not RV friendly. Also, please do not take Old Priest Grade. This route is for passenger vehicles only and is very steep and windy. Weight limits do apply and are enforced.
Take Interstate 5 to Hwy-99 toward Merced. Take Hwy-59 north to Snelling. In Snelling make a left hand turn at Hwy-J59. Continue on Hwy-J59 until it comes to a end. Turn right and you will be on Hwy-108. Continue approximately 4 miles and make a right hand turn on Hwy-120. Stay on Hwy-120 through the town of Groveland. Continue 1/2 mile East of Groveland on Hwy-120 and then turn right onto Old Hwy-120. Follow Old Hwy-120 for 1 mile. You will see Yosemite Pines RV Park and Campground on the left.
3. Keep in mind that the campground is 22 miles from the entrance to Yosemite. You then have to drive another 20 miles to Yosemite Village. So figure the drive in will be 1+ hours.
Tom and Katharine
'07 Winnebago Tour 40TD, 400hp Cummins
RVing for 19 years & 150,000+ miles