Job interviews

Currently, I am doing consulting work in business analysis. It means I have a lot of flexibility (which I love). However, it isn't exactly what I want to be doing 10 years from now. So, I have been casually applying to positions in the area. However, the fact that I might get an interview scares me immensely. Not so much because of the interview questions, but getting around a new place with a disability. Will I be able to navigate the building? Will there be stairs? I recently had two interviews, and both ended up okay. The interview room was very close to the front entrance so I did not have to walk very far, which is usually the case for interviews. But it is not guaranteed. Sometimes it is frustrating to think about being up against other candidates who don't have walking to worry about in addition to the actual interview. I also wonder when the best time to disclose my disability is. Should I tell HR before the interview? Then I can request that the room be close to the front entrance. I'm afraid that creates hesitation before they have even met me. Should I mention it in the interview? This seems the most natural to me. I don't want them to get someone they are not expecting - I want the company to be okay with hiring someone who won't be able to run around the office, but has the brains, skills, and personality to make up for it. It does mean that, even though they probably won't admit it, they will take my disability into account when making the hiring decision. Or, should I wait until later, maybe after the offer or even after I have been hired? This is hard for me because I feel like I haven't been honest, like I was hiding a part of me from my future employer. It doesn't seem like the right way to start off a relationship. But apparently I should never have to disclose my disability to my employer, but honestly, even though I can hide it pretty well in short walks on a good day, they are going to notice something is wrong. And then it is just awkward.