Ruck-A-Chucky Rapids Trail is a 6.3 mile lightly trafficked out and back trail located near Foresthill, CA that features a river and is rated as moderate. The trail is primarily used for hiking and trail running and is accessible year-round.
From where the trail starts, you are following a dirt road that is closed off from November through March. While the trail itself isn't much to look at since its a dirt road, it does offer great views down to the river, and to Summit Hill, with various vantage points and heights to take photos of the river from. It was fairly cool when i went but it was mid November. There were combinations of shady and exposed areas so bring sunscreen.
Make the drive down to the campground area. We made the mistake of deciding to hike down (and back up) the road which isn't that nice of a hike. Once down there though its a beautiful area.
This is a beautiful trail along the Middle fork of the American River. It is part of the Western States trail. You park by the campground or a little further up in the fee areas. From there it's a dirt road you follow for about a mile to the WST entrance gate. You see the gorgeous Rapids before this tho. It's super hot in these canyons in the summer with temps that reach 100+ easily. Bring plenty of water and sunscreen. From the WST entrance, it's 4 miles to Fords Bar.
Driver's Flat Road is pretty steep, I would recommend at least an SUV, although it is usually possible in a car. This is part of the Western States Trail and leads out of Ruck-A-Chucky campground (a fee area) following the river, although you will have to walk a few miles before it actually drops down to the water at the first sharp bend, which is as far as I've ever been. Up to that point it's a fair dirt road, afterwards it turns into a slightly overgrown foot trail. Apparently you can follow it all the way to Foresthill if you want - about 15 miles away, and it doesn't appear to connect to any other trails, so consider this an out-and-back. The best time to go is any time but summer, it gets hot and the first stretch of trail is on a south-facing slope that will be covered in dry grass, winter and spring are best if the road is open. Although not really needed for this one; you can pick up a free, non-topo trail map at park HQ on highway 49, there's also a big map posted at Ruck-A-Chucky.
Pretty gnarly to get to, but easy once you get there. Hike is the best just 1 mile in at the falls which are down a tougher trail to navigate (no kids, dogs or the like). The rest winds along the river for the most part.