From Las Vegas, head northwest to El Porvenir, then drive up the road to Johnson Mesa. Before you get to the top, take Forest Road 291 that drops down into the canyon. This road had big mud holes when we were there - high clearance is required; 4WD would be a good idea. Park at the location given and look for cairns showing the way to a faint trail that first goes straight downhill, then turns left to drop more gently. This trail connects with another trail in the bottom of the canyon below the confluence of the main and north forks of the Blue River. From the confluence, hike up the main fork a short distance. From the cache location you can see the top of a forty foot waterfall. After finding the cache, continue up the main fork to see more smaller, but still beautiful falls.
If you own private land farther down the Blue River you could make this a shorter and easier trip, but most of us won't be able to get past the locked gate. Beware of poison ivy near the water.