R&R a window is easy, but a fairly big job. I recommend getting a willing helper, as you will need someone outside and someone inside. First the blinds and valances have to come off, then there are screws all the way around on the inside that come out, then remove the trim from the inside and push. Your window will then fall out to your outside helper. That is when you go outside to take 1/2 the window.
Harbour Freight have glass suction handles, $5 for a single, $10 for a double. They really help.
While you have the window out, check the opening to see if it has been waterproofed. Now would be a good time to add some. Get some 1/2" butyl tape at a glass shop, you will need this around the perimeter of the window when putting it back in. Peel the tape off the roll and stick it to the opening, leaving the plastic on the exposed side of the butyl, with the ends of the plastic tape folded back so you can grab hold after the window is in place and still loose (one or 2 screws for safety), then pull the tape off and tighten up the window to the inside trim. When the window is back tightly in place, use Lexel caulking around the perimeter, NEVER use silicone. Failure to check or renew the waterproofing, use new butyl tape and properly caulk around the outside will allow water into the side wall of the coach, potentially causing delamination and other issues.
Much easier to remove the passenger chair and use the doorway for big items.