As an educator, my experience is that most museums allow you just to walk in and browse at your leisure. Some charge admission (like Henry Ford Museum Greenfield Village) and some do not (like the Toledo Museum of Art or the Natural History Museum at U of M...however a donation is generally appreciated).I suggest you visit the museum s web site for details.
It depends on the Museum. The ones in the city of Detroit usually have fees, even the DIA. Once you pay the fee you can walk around at your leisure. If you would like a tour, you have to pay an extra fee (usually). The tours usually come in two types, a sound tour (they give you headphones that tell you about the paintings) which you can do at your leisure or they can do one with a tour guide. It comes down to the museum which you are thinking about visiting. I suggest you look up their website and either call them or find the information about admission.
While it depends on the museum most allow you to just walk in (after paying admission if applicable) and look around by yourself. Most museums are designed so that an individual can wander around the exhibits and take their time with things that interest them. Some museums offer specialized tours to individuals or groups at an additional cost and some even have free tours at various times. These tours are generally optional.
Depends on the museum ... At the DIA you can just walk around, but if you are looking for a guided tour they have a couple of options. One is to schedule a live human docent to walk you through the place. This is best if you have a small group of 10 or so. Two, I believe the DIA has headsets you can rent. When you approach an exhibit hot spot the recorded docent tells you about what you are looking at.
Depends if you have a gun or not.