Thank you all for your experiences and advice.
In addition to asking for help in this forum, I also emailed Newmar to see what they recommend regarding the removal of the peninsula.
I received a drawing of the peninsula, which I attach below, as well as the following feedback from Newmar:
"Thank you for contacting Newmar Customer service. When it comes to technical assistance, Newmar customer service does not provide instructions on installation and repair of most items. However I did attached a print to help you visualize the build and I received some advice from service.
Option 1) if there is a switch on the cabinet end next to the sofa it can be removed to gain access to the inside of the cabinet.
Option 2) if there is not a switch the drawer to the right would need to be removed then an access hole cut into the panel between the cabinets.
Once you have access there is a block that hold the magnets mounted to the top front that needs removed. The magnets stop the cabinet from coming out."
pull out drawer.pdf
I don't have a switch on the end of the cabinet next to the sofa, so option 1 doesn't apply to my situation. I can't imagine a big enough switch which, when removed, would provide adequate enough access to the area behind the peninsula.
For option 2, I assume that the drawer in question is the one just to the right of the peninsula, between the stovetop and the dishwasher. If I had a drawer instead of the dishwasher, I could see how after removing it, you could have enough room to cut an an access hole, but with just the small drawer removed, it would be very difficult. It seems that option 2 won't work for me either.
After all that, I embarked on a voyage of exploration.
First, I removed the drawer between the stovetop & the dishwasher and also removed the stovetop, so I could better understand the access I have available without any cutting.
I was hoping that the area under the stovetop would be open, but unfortunately there is a metal tray which restricts access below that.
Removing this metal tray would provide better access, but it is attached to some wooden brackets with 4 horizontal screws. The 2 rear screws are back against the outside wall and very difficult to reach. Even if you could reach them, there isn't enough space for even a stubby screwdriver. I guess if you were flexible enough, you could try a 90 degree screw driver attachment of some sort.
Looking through the drawer opening, you can see an already existing access hole into the area behind the peninsula.
I used this access hole and a borescope camera to get a better view of the space and the back of the peninsula.
There are two drawers in the peninsula. The top drawer does not offer any access behind it, but if you remove the bottom drawer, you will find another access point through the back of the peninsula. Kind of difficult to reach without actually removing the peninsula, but it could be useful in some situations.
Based on the picture above and the picture posted earlier by someone else, it appears that the information from Newmar is not correct. It is the metal plate that holds the peninsula from completely sliding out, not the magnets.
So, the bottom line is that if you could get to the metal plate and removed it, the peninsula should slide out of the cabinet just like a regular drawer. Keep in mind that the actuator wires will need to be disconnected before completely removing the peninsula.
In my particular case, the existing access hole at the top of the wall between the dishwasher cabinet and the peninsula cabinet will be sufficient for me to fish a cable and complete my project.