With a month to go, there's not a whole lot you can do. If you can do some hikes w pack, that's best. If not, work capacity routines should help. 1/4 mile on the treadmill set at15%, 100 step ups onto bench and 20 pull ups, for 3 to 6 rounds is good stuff.
But really at this point, as specific and injury free should be your main objectives.

in general, lower weight will be less workload. of course depending on how long you'll be at altitude you may lose weight from having no appettite, so having some fat is good. but a weight built up from weightlifting is definitely not optimal. but I agree with bird that at this point, there's not much you can do. could loose a few lbs, but probably won't matter too much.

I disagree about there not much I can do at this point. Fasting, I lose 1lbs/day of pure fat. Of course, I can't fast completely between now and then and lose 20lbs and still be in optimal health. I am down to 190lbs, just because I felt I put on too much weight lifting and eating. I will probably target 185 for my trip. 5lbs makes a big difference, at least as far is the other activities I do. I always gain weight on vacation, but if everyone loses as much weight as people have said, I don't need to get on my flight with 6-pack abs.