need tire advice

Last week I had my first blowout. Nobody's fault but mine, I was going too fast for the tires (rated at 65), I was doing just shy of 75. Normally I drive up and down the West coast but this trip I turned inland a bit and went through Nevada, Utah, Idaho towards home in B.C. What I found was that the speed limit is quite a bit higher in this area than on the west coast. I would like to get some tires that can handle higher speeds on a regular basis.
So I am going to replace all four of my trailer tires and was wondering if anyone has a suggestion on what tire to get.

Here is what the tires need to be able to handle:

Fifth wheel trailer weight 9500 to 10000 pounds total
Hitch- about 1600 so 8400ish on the tires

I would like to be able to run at 75+ when possible
Current size is 225 75 r 15 if that matters

I have put around 25000 to 30000 miles on my 2006 fifth wheel with no tire issues. Started with the factory originals and changed a few years ago to Goodyear marathons. No problems other than the blowout last week. I knew I was pushing the envelope that day but we had a scheduling issue we were dealing with.

In the future I plan on using the inland route a little more which means higher speed limits so does anyone have any input on what tire would best suite my needs?