For cole slaw, shred it at home. Zip bag it with the dressing separate. You can also get pre-shredded ingredients at most stores now and add your own dressing.
Most cutting and chopping can be done with knives. We have a whisk for blending eggs and a two slice toaster that toasts our english muffins. The microwave came with the rig.
We plan our menus to use as simple a prep as possible. Most prep work is done at home and zip bagged for the fridge or freezer. Meals needing extra appliances we simply don't fix while we're in the RV. This keeps all the extra clutter of multiple appliances off the tiny counter space and cabinet space. Remember that extra clutter weight can affect your fuel economy too.
Mashed potatoes and other multiple stepped dishes rarely appear on our travel menu. If they do, we use an old fashioned potato masher and muscle. We've never had a need for a mixer when it was simple enough to use the masher or other hand tool that fits in a drawer.