You can replace the micro with whatever you wish. It may be hidden, but it just plugs in an outlet like any micro. Just remove the old one first, and then measure the size of the opening. Then find something that will fit the opening and figure out how to secure it.
Since microwaves are generally enclosed in campers, your new one should be front exhaust, especially if that is what the old one was.
to the forums, glad to have you.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT