I hiked this on 7/28/2013. I can tell you for sure, as accessible as this Split Mt. might look, it was a pain to make it to the trailhead and also to the top. I ran into a lot of conflicting info from the start. Fist of all, the Fuller Rd is the way to go. Take it until the asphalt ends. Follow the dirt road to the first split that has a sign NO PASSING PRIVATE PROPERTY. Make a right there and follow the road. Without a GPS I've never made it. I made the mistake of taking McMurry Rd back to the street and I drove for almost an hour and 30 minutes. That road it is in a way worst shape then Fuller Rd, at least for a sedan. I also need to point out I drove a sedan Nissan Sentra. I had no choice.
The trailhead it located at the North side of the parking lot. I did not know. There it is a trailhead at the Southside of the parking lot which I took. That trail merges with the official trail eventually but I found that out the hard way. Taking this trail on the South along the creek and trees was much sorter but I keep losing it and finding it until I lost it completely. By mistake and out of frustration at one point I started going straight up the hill until I found the official trail that I followed all the way to Red Lake. My GPS said 3 miles to Red Lake. The official count is 5 miles. At the lake I found out from some campers what I did wrong/different and all that about the trailheads. From Red Lake to the summit it would take one 3 hours one way. There is no trail and just uphill rock fall hiking. Of course, as all went wrong for me the whole day, I got all the way to the last ridge when the clouds, high winds, almost no visibility and thundering, hail and rain started very strongly on me. I got so concerned that, with the summit within reach and with pain in my throat I had to go down. I felt it was too dangerous to make the last 400 ft elevation on that weather. Of course, on my wan down, rushing as much as I could to go out of that thundering and hail, I lost my camera. So if you find it (a black point and shot Canon) let me know. Of course, when I got back to Red Lake there were no thundering, clouds or hail. Like I said, things worked backwards for me that day.
On my way down it looked like everything got hit with a lot of the rain that I mentioned. People probably rushed down the trail since I found a camera (silver Canon with about 40 pics on it, all from Red Lake and Split Mt.). If yours, hit me up I'll be glad to mail it.
If this hike will be done in two days, it’s easy. Go to the trailhead, hike to Lake Red, wake up early AM and hike to the summit. If this hike will be done in one day, like I did, start as early as you can. There is time enough to do it in on day. I did it, but the lack of info drove my frustration through the roof. I was convinced reading the maps that there were 5 miles from the trailhead to Split Mt. but I was wrong. There are 5 miles to the lake. I was alone and I have a good pace on the trails. I wish I was at the trailhead at 5:30 am not at 9 am. Also wear long pants. I wear shorts and I ended up with a million cuts on my calves. Them bushes are not to friendly.