You might be OK with 72's. Here in Denver I'm running 74/80 on a 650 DP on 10.2:1 360 with a 216 @ .050 lift cam, headers and LD4B intake and I think It's still a little lean.
Just bring a pair of 68s and 70s with you as well as the appropriate tools with you and a couple bowl gaskets just in case. I would'nt worry about the secondaries unless your going racing while your there.
Don't be suprised by the loss of power at altitude. 2% loss for every 1000' is the rule of thumb but some say more. There's really no way to make up for it short of super/turbo/charging or increasing compression ratio. Just keep an eye on the exhaust and look for the tell tale black smoke.