The last mile and a half requires a high clearance 4 wheel drive vehicle and a lot of nerves - the trail is marked intermediate on the map - Don't take your wife's brand new Ford Explorer and expect it to look the same when it gets back.
I was able to do it with a full size Jeep Cherokee (completely stock - no lift kit or anything), but I added a few scrapes and dings to it in the process. If you don't have a 4 wheel drive vehicle that won't mind a few scratches, or an ATV or Dirt Bike, then you can walk the last 1.5 miles fairly easily. I did see some people with mountain bikes up there but I think you would be walking your bike most of the time on this particular trail.
The cache itself is in a white 1 gallon pail partially buried so the top 1 inch or so is showing (for now, I will have to go back and check it in the spring after the rains). The new container is a kitty litter container (25 lb size) spray painted with a reverse cow motif. It is not buried in any way (the guidelines for placing caches have changed in the last 18 1/2 years), but is nestled in some bushes about 30 feet above the trail. I think I placed it high enough above the creek so it should be safe from the winter floods. It's not visible from the main trail, but from a small game trail that leads under the bushes.
I intend to put some more spoilers here, but don't look for them right away.
Update Aug 2019: I do not think the road is passable anymore unless you have a seriously modified Wrangler or like, an ATV, or a dirtbike (250cc or above). As such, I have changed the difficulty and terrain to 4.5 each.