I found a neat glitch...
I was trying to see if I could make my way around the river bed opposite Dodge City when I found a reverse blue hell.
On the other side of the river to Dodge City, there's a cliff near the river bed furtherest away from the ferry operator.
On your horse try and walk around the cliff by walking or ride the horse hard into the river or pushing at the cliff, it wont let you but keep trying, if you do it correctly you should float up into the sky and get a birds eye view of the map.
I tried doing it again and this time I went through the cliff and came out on the other side (which is what I was trying to achieve in the first place).
I followed the trial as far as I could go which led me to a waterfall. I tried jumping over the waterfall and fell straight through which led me to a kind of blue hell.
I did this just before while playing Gun, so I went over to the Gun message board over at gamefaqs.com to see if anyone else had discovered this glitch and someone had posted that they had.
Oh well, it still is a neat glitch.