Honda Gas Generator to run in tool box: Good or bad idea

I was wondering if anybody had experience with putting gas generators into small boxes. I have a box truck conversion RV that has a tool box attached underneath the side. This box seems to work perfectly to house the generator and protect it from the elements while still keeping it out of the living area. It just barely fits inside.

Currently I take it out of the box to run it, but I was thinking that it would be more convenient to leave it in. Then I would wire it to the battery bank and it would always be ready to go.

One time I ran it inside the tool box for 10 minutes with the door open and I didn't have any problems. However, I've read that in the long run this may choke the intake opening with Carbon Monoxide and so I haven't done this since. The manual says to have at least 3 ft above the generator and to only run in a well ventilated area.

I was wondering if I drilled a few holes, installed a fan, and isolated the exhaust if I could then run it without problem inside the tool box all the time. I would probably put some one inch foam board around it to help with sound, but I realize that I would also need to have the proper fan and ventilation holes.

The generator I'm using is the Honda Companian EU2000i. Please refer to the picture link above. If anyone has experience and could tell me if this is A: doable or B: a bad idea; I would appreciate it. Thanks