There is a trench, 4.5' wide by 3' deep with vertical sides, impassable by atv, between 1.5 and 2km up.
The bottom of the FSR has a sign that says "Slollicum Peak closed Mo-Fri". The second gate has a sign saying "closed". Since it was Saturday and the gate was only dummy locked, we went ahead. Road is in great condition, no potholes, no water bars. One steep section that is a bit loose but any car with a bit of clearance should make it (for reference, I drive a stock Rav4 but have good tires). One bigger rock on the road that could be moved aside but tons of space to just drive around it so we didn't bother.
Drove to the Cascade Bay road - snow free up to there.
Some rought spots, but nothing any clearance 4x4 can't handle.
I drove my AWD SUV to km 4 and stopped at the closed gate. The road was in very good shape with a few potholes and some easily manageable water ditches across it. I walked past the gate and up to the end of the road. Deactivation ditches got much deeper around km 6 so you would need good clearance and likely 4WD. Patches of snow started about km 6.5 and the road quickly became snow covered. The photo is around km 5 but represents how the road is from its beginning g.
To touch on the last update from Justine, the gate at 4.25km's is still open. The waterbars are fairly aggressive so I would agree with what Justine said about long wheelbase's probably gonna be dragging bumpers. The ice storm a few weeks back dropped a few trees over the road right at the 6.7km left fork so we parked there. Only 500m distance to walk to get to the creek crossing if you don't bring a bow saw or chainsaw.
I connected to this road via the slollicum trail from the 200 branch below. From where the trail intersected the road I could see an open gate a few hundred meters back. Snow started around 800m and was consistent by 850m. Larger cross ditches were present after about the 6.5km mark that would require a HC 4X4, but providing the gate is open you could drive all the way to where the trail to slollicum leaves the road and goes into the forest. A range rover was parked at the trailhead when we returned from the peak.
Likely going to be used for logging in the near future. I believe it is gated, probably near the start.