I had a posterior approach - it's someting of a misnomer, because it is really from the side...I was going up and down 7 steps 3 days after surgery (but only once a day, with standby assist.)

PLEASE do not let the fact that they are doing a posterior approach concern you. So I don't need to repeat, please read this recent comment:
https://connect.mayoclinic.org/discussion/total-hip-replacement/?pg=12#comment-973891
For the next 2 weeks, it would be good to concentrate on getting your legs as strong as you can before you head in to surgery. I bet there is a sheet or list of exercises in pile of stuff from your doc - highly recommended!

Also, unless your housemate(s) are good cooks, get some easy meals into the freezer, some comfy pull-on pants to wear, a shower bench & a seat riser for your toilet. With grab bars for pushing yourself up. And a Cryo-cuff with a hip pad, or lots of large ice packs. I used them nearly 24/7 for the first few weeks, several times a day thereafter.

Come on back and let us know how you do - we're here to hold your hand. It will all be worthwhile in the end
Sue