This boulder is almost never climbed, I have driven this road literally thousands of times and seen cars parked on the road where you would park to go there only a handful. It's a very nice, large boulder with a good number of problems on it, the area is very peaceful, it's ideal for winter bouldering and there's enough to do and explore in the area to easily make a half a day out of the adventure.
There is one bolt on the top of the boulder, looks like a pretty old home made hanger if I recall correctly. This is a large boulder so I would recommend a couple pads and good spotters.
If you have any additional information post a comment on it and I'll do an edit.
For directions I want to be slightly more clear than I've seen elsewhere. From I-10 and Ina you head west on Ina 3 miles, past Silverbell and keep going until you see Wade road, there will be signs telling you to turn left for Picture Rocks Road, if there are cars in front of you the flow of traffic is normally going that way as well. After the left turn you will drive almost exactly 3 miles where you will see a 35 MPH sign. If you park at the pullout on the right side of the road a few hundred feet before that 35mph sign I think you would be better suited. When you park, look to the north at that huge wall, the bouldering book says to look for a section of the cliff that is flat and lower than the rest of the cliff, I don't think that huge boulder half way up all that scree was there 5 years ago (when the descriptions I've read were written) but it is now and that's what you should aim for. There is a wash right there (where you parked, it should be fairly small and might be a little tough to see right away) and it makes for easy walking and no bushwacking. You can take that about half way back. Just keep following the main flow. Once that wash tries to go off to the west (or left) where the large 30 foot steep rocky slope is turn your direction to that large boulder.
You're going to want to walk like you're going to that. The red boulder is at the bottom of that slope under that huge one and it should be pretty easy to see if you have been there before but it won't be obvious until you're pretty close if it's your first time.
The approach is about 0.5 mile so it isn't too bad and shouldn't take more than about 20 maybe 25 minutes. I was able to get there and back with 3 kids in tow in about an hour and a half.
Mountain Project's determination of some of the classic, most popular, highest rated routes for Red Boulder:
I went out here today. It's a pretty mellow hike, and there are quite a few other boulders nearby that look to have potential.
After I was there for about 45 minutes or so, enough bees had gathered around me that I decided to leave. Initially there was only one or two, and by the time I left there was more than 50 bees swarming around the dogs water dish and my ankles.
I visited this area in or about 2005. We hiked around a bit to see if there were any other potential problems, but found nothing enticing enough to warrant further investigation. Still, there are a couple of good lines on Red Boulder. If I remember right, there is some old relic hardware on top. If you like solitude more than climbing, this is a great outing. The hike out takes you through some of the densest saguaro forest in the Tucson area.
This area is SUCH a tease, I spent a lot of time hiking around here the past few months. I would see something that looked amazing but it was such choss you could protect it with a hammer and nails /: I did manage to find one AMAZING line unlike anything else I've found in Tucson but who in their right mind is going to hike 2 miles with 1,000 feet of elevation gain for one 40 foot line.
This boulder is great if you want to hike and do a little bouldering not the other way around.