The fit guide you are referencing is for the exterior. The frame and electrical components are for the chassis which is a 2010 Ford Van Chassis for the E-450.
My guess is you are looking for anti-sway stabilization bars. These help reduce body roll and help you maintain control with crosswinds, passing traffic, uneven lanes, etc. I recommend the following parts confirmed to fit your chassis:
Roadmaster Rear Anti-Sway Bar for Motor Homes # RM-1139-147
Roadmaster Front Anti-Sway Bar... view full answer...
The Jensen Stereo part # JWM60A will work great as a replacement for your AWM960 but the connectors are not the same and there isn't a plug and play adapter. You'd have to wire your RV's wiring to the new stereo using the diagram I attached as a guide. view full answer...
I have another option for you, but roof vents are only 14" x 14", and we do not have any smaller covers.
If you can tell me what the model number of your roof vent is I would be happy to confirm the correct replacement roof vent lid for you, or you can use the MaxxAir UniMaxx Universal Replacement Lid # MA00-335001 in white or # MA00-335002 in smoke.
Both options mentioned are universal and use a universal hinge that gets screwed to your existing roof vent so they will work with any roof... view full answer...
For a steering stabilizer that is a confirmed fit on your 2019 Winnebago Outlook 27D use the Roadmaster Exact Center Steering Stabilizer w/ Custom Brackets # RM47MR. view full answer...
The Camco RV Rain Gutter Extensions # CAM42110 that you referenced are exactly what you are looking for as these are designed to divert the water away from the body of the RV so that it doesn't run down the side of it and cause black marks. view full answer...