>>1894359What you need to do depends on how hard you're going to exert yourself and how high you're going to be but basically don't be arrogant and/or obese and you'll be okay - most of the cases of HAPE occur in either fat fucks (who have trouble getting oxygen anyway) or in athletes who push themselves before acclimation. The former are mostly retarded boomers who think that chasing sheep at 12,000' for eight hours is like that one time they went chukkar hunting for an afternoon at 3000' in California and the latter are mostly twentysomething fitness junkies who think that because they're in good shape the laws of physics don't apply to them and try to do a fourteener the same day they fly in from LA.
Drink lots of water, rest as needed and don't try to hike hard (easy hikes and walking around town are okay) at 10,000'+ without at least a day or two of acclimation first and you'll probably be fine.
>>1894367I don't know how familiar you are with western states but unless a piece of public land is specifically off-limits it's generally considered fair game for foot traffic so with a GPS and good land ownership maps you can go anywhere you want. I personally use OnX maps and I recommend that you do too because pound for pound it's about the best $120 I've spend on anything /out/ related.