I brew a bit above 7000 ft., boil at 198 F, but have never had any issues. I use the same methods at low altitude, always a 90 min boil, and haven't noticed any effect on hop utilization or anything else for that matter. The biggest problem I have is keeping the temps up for ales (it snowed May 28th), as a result I lager a lot. If you force carbonate, you'll need to reduce your psi significantly, however.
Baked goods, such as my sourdough bread, do require recipe adjustments as noted.