I was able to find online that your 2020 Forest River Vibe 28BH came with a 20 foot awning like what the Solera Smart Arm 12V Power RV Awning - 20 Wide - Programmable - Black Fade Item # LC517517 size is so this would work really well for you. view full answer...
The etrailer eDream Supreme RV Mattress - Hybrid - 75" Long x 60" Wide - Short Queen # e97FR has a shipping weight of 112lbs but you could subtract 3-5lbs for the cardboard/packing materials. view full answer...
There are no warranty implications involved with installing a slide topper like the # LCV000168104 you looked at. Lippert doesn't list a capacity, but did state that accumulating snow should be swept off regularly before it can accumulate by more than a few inches. It won't likely hurt the topper itself, because it's going to be pretty close to the top of the slide but the slides don't like having extra weight on them. view full answer...