Hi sung. Happy to answer all of your great questions, but I must emphasize that everyone's recovery is different, and there are differences between the recovery protocols from the surgeons. Based on that, I don't think there is such a thing as a "normal" recovery, so as you said, these answers are just "in my experience" after my two hips, ten years apart at ages 56 and 66. I strongly suggest that you follow your surgeon' guidelines and not mine, unless of course they match.
How bad is the recovery? This is a very subjective question based on your expectations, experience with recovering from injuries and surgeries, pain tolerance, and patience. In short, I would say that the first two weeks are kind of rough and many of us wonder what we we have done to ourselves. The next four weeks are challenging. Then things start getting better fairly fast with lots of ups and downs. With the top surgeons, the pain is generally well controlled and not much of an issue. For me the challenges are mobility, since my operated legs were basically worthless logs attached to me, so simply moving around was a sizable challenge. There is also a fair amount of fatigue and severe bruising like you have been hit by a truck. Depending on how much opioids you take, your digestive system goes on strike, and is not much fun to get back on track.
Walking aids? My two hips were similar; two crutches for two to three weeks, one crutch for another two weeks. Canes are okay for getting around the house, but not really functional for the daily walks that are so important. During the transitions, I would take my one crutch with me, and only use it as needed..
Recovery: Walking is a big yes. Many surgeons will tell you that this is absolutely the best thing that you can do, because it addresses pretty much all of the muscle groups in the way they were designed to work. My routine has been: First week-one to three blocks. Second week-½ mile to a mile. Third through six weeks- 1-2 miles. and after six weeks I am doing 3-4 miles. These walks are always at least once a day, and often twice a day. In addition, I do the conservative exercises prescribed by the surgeon, and some light upper body weights in order to get my breathing going and work up a sweat, which I feel is important.
At 6 weeks I add PT, pool work, stationary bike, light leg weights and partial squats, some sports cord exercises, and introduce some stretching. I think that controlled elliptical would also fit well after six weeks.
My surgeon allows all activities at six months, as long as you build into any new activity gradually. I started skiing all day, every day at exactly six months. Due to the seasons, I started tennis, surfing, and windsurfing at 10 months. I should add that I had some issues with trochanteric bursitis the first summer that I returned to tennis, so it was very off and on. Since the second summer, I continue to play aggressive singles tennis about 4 days a week during the summer, as well as surfing and windsurfing every day. I still ski every day all winter.
Hope this helps. As someone who is just passing the six week mark on my second hip, I would not encourage anyone with the idea that it is easy; I really do not think that it is. However, once you get past those first couple of weeks, you will notice little things almost every day that you could not do the day before. If you learn to look for and enjoy these small daily victories, the journey is very doable.