Hills will suck, but really there’s nothing you can do except what you already know. It will take 2 weeks minimum to begin to acclimate and more like 6 before you feel more normal. I used to spend my summers in Santa Fe, NM at 7,000 ft. The first couple of days were difficult, but I just stayed away from steep hills. I also put away my heart rate monitor as it was telling me I was about to die.