Got back from Relay Creek last weekend and thought I'd give an update on the access road. We were in an older Toyota Tacoma and made it to the trailhead with no issues. There are a number of off-camber sections with some steep exposure about 3/4 of the way but it was more of a courage calculation than a capability one and they were no problem. About 6km from the trailhead there is a steep, rough hill with an off-camber section that is fine going in but coming out takes some doing and I wouldn't do it without a full HC 4x4. There were about 7 trucks at the trailhead on our way out (all HC full 4x4) so it is done regularly. I have a Subaru Forester that I would have had no problem getting to the top of that hill then I would have walked the last 6km. There were multiple vehicles parked along the side of the road before some of the mentioned sections though so exercise your own discretion.