Cooling system

I was wondering how much pressure is supposed to build up in the cooling system? After running for awhile, my radiator hoses get pretty hot, enough to where the clamps "mold" themselves on the hose. The problem Is that after running awhile, there is so much pressure in the upper hose that you can't even squeeze it at all - is all this pressure too much or is it normal. Oh yeah, it overheats as well after 45 mins or so and doesn't drop.

Well I have been flushing and flushing the radiator and plenty of brown water keeps coming out lol. So I am using a strong flushing agent at the moment. The T-stat was replaced about 200 miles ago. The cap, I don't know what's up with that. The weird thing is that when it did overheat, the entire cooling system back flowed when and only at the instant I cut off the car. It completely filled up a near empty overflow tank and continued to overflow out of the dispense tobe and then on the ground for another 15 seconds after the overflow tank filled up. I don't know what to check next as i've never seen anything like this. The radiator is original with 267k on the odometer and a lot of things look abused or nearly-never serviced. Like I said though, The system doesn't have a lack of pressure, it almost seems to be too much pressure and by far. I don't know how the hose doesn't burst sometimes. Any additional ideas?