I'm thinking the generator should be on a sliding tray. Look at the attachment frame on the bottom, there are usually clips/pin/bolt system that can be released and the unit slid forward for service, at least somewhat. All coaches are different though.
Some are on rollers, some just sit there. Either way it usually involves removing something you dont want to, like the exhaust.
Here is a video of a similar gen being removed:
https://youtu.be/oDsYEd5725U
Fast Forward to about the 3 minute mark if you want to see how he does it.