Do you have advice on removing upper cabinets and adding open shelves?

Jennifer, I had to research how walls are built in a modular home & believe they're slightly different than stick built ... but not enough to worry about. Exterior walls are same 2 x 6 in while interior walls in modular homes use smaller 2 x 3 in studs. As long as you securely attach your new shelves to wall studs, you should be okay.

Found nice article showing with photos, how walls are constructed in modular homes.

What you may find helpful is understanding how cabinets are securely hung in traditional construction (afraid I couldn't confirm same for modular but guessing it's the same). When designing a kitchen, noone wants their cabinet placement to be controlled by the wall studs. To remove this constraint, blocking is placed on kitchen walls over the studs and behind the drywall. Here's an article (great photo too) on blocking ...

As long as your shelves are long so you can attach them to multiple wall studs, you don't have anything to worry about. If however you were going to get creative with a collection of boxes that aren't 3 ft (studs are every 16 in) or wider, then you'll need to confirm there's blocking in your walls.

We did this to a section for our cupboards. Here’s how we did it: https://www.frugalfamilytimes.com/2015/10/kitchen-update-for-way-less-cash-how-to.html?m=1

Hi, Jennifer!

I, too, have a modular home and used open shelving in place of upper cabinets. I spray-painted metal angle brackets then attached them to the wall studs using long screws, and the shelving made from 2x10 lumber was secured to the brackets. (Though if I had to do it over, I would paint the brackets to match the wall so they blend in!) I hope this helps!

If your cabinets are secure, why not just remove the doors. Paint the interiors after filling the holes from the hinges. You can trim them out to your own aesthetic, if you wish.

Hi Jennifer, many of the rustic kitchens had lots of open shelves, is that the look you are going for? Hope these help you out

https://www.youtube.com/watch?v=QnFMFksu4c8

https://www.bhg.com/kitchen/cabinets/makeovers/how-to-convert-kitchen-cabinets-to-open-shelving/