Walker Mountain is a Southern Oregon summit that could be a drive-up for those with a fully capable 4x4. However, the roughest part is also the start of a decent hike and getting to that rough spot is easy with a vehicle with decent clearance. Note that there is another Walker Mountain in Oregon - this is the one near Grants Pass.
Take Exit 58 from I-5 (Grants Pass) onto Scoville Road, then left onto NE Scenic Drive - you'll round the corner onto Granite Hill Road. Continue about 6 miles, eventually keeping left to go straight on Winona Road. Turn left onto BLM Road 35 59 and go 2.6 miles where the road widens and starts to descend. There's a sharp left turn there with a road bed that is heavily rutted - I chose to park and walk from there. The road has two switchbacks - at the second you'll see a rough track continuing up the summit ridge - take that. From the parking spot it's about 1.4 miles to the summit where there is a small clearing and a fire ring.