Denali......I've never tried to replace that circuit breaker, but I did remove the upper cover without removing the generator. I don't know if you'll have access with the upper cover off, but I'm thinking you might from what I remember.
The upper cover requires removing all of the screws from the passenger and driver's side of the cover. I then slid the generator out, sat behind it on the ground (under the coach) and removed the rear screws. It's a very fastenating little engine with the cover off
I had to do this because I couldn't get it to accept coolant after changing it....learned how later.