Greetings & Welcome aboard.
I find it odd that your unit did not come equipped with a gen set.
If there is a bay for a gennie should be fairly easy to have one put in as the wiring and fuel pumbing should be already in place.. unless the previous owner used the gen set delete option.
You really do not want to have to deal with a portable gen..It's a royal PITA... permanent mount is the way to go.
And go with the larger gen set that was an option when coach was built.
https://thormotorcoach.com/media/doc...ales_Sheet.pdf