Nancy at Dr Gross's office can guide you through any of these questions, and is great about it.
From my own experience and that of many others; yes you will need a toilet seat riser. You will definitely need crutches, and they will have them for you to purchase if you do not already have your own. My memory of the Marriott is that the toilets in their handicapped accessible rooms are slightly raised, at least I do not remember it being a problem. And yes, worrying about everything prior to surgery is very normal. I think it would be very abnormal not to. I had my first hip done by Dr Gross 10 years ago, and I am going back to have the second one done in April. I am not as worried as the first time because I know to some extent what to expect, but there is still nervousness about how it will go this time. I can say that once you are there and they start taking such good care of you, the nervousness starts to go away.