Well I have no experience with the toyota, but I have an '01 f250 7.3 and tow a 9-10k travel trail + 1000lbs in the bed of the truck from Denver over the passes at least once a month.
Payload is not an issue for the truck. It is very stable with no sway bar and a basic WD hitch.
As to speed I can pull all the passes well and at the very steepest spots maintain 50-55. Mine is modded pretty good from stock though (with 35in tires, which hurt)
I think in order to be happy with the power of a 99+ 7.3 you will need to do a few mods including 4in exhaust, intake, gauges, 6.0 tranny cooler and a chip. I would plan on adding $800-1000 to a stock truck to get the performance you want. If you do that it would probably out perform the toyota, but stock I dont see it......A better towing platform by far, but when looking at stock I dont see you getting any more power over what you have now.
Also regarding people talking about HP and a tuner. For towing in the high mountain passes the biggest tune you will be able to run and keep EGTs in check will be a 40hp, maybe 60. Anything else is not worth comparing because the EGTs will be through the roof.
BTW 7.3 prices in denver are pretty high, especially for crew cab trucks. I looked for a long while before I found a good one.
Good luck.