Both my wife and I are pretty short. She's 5'1 and I'm 5'5 and reaching the top cabinets is a problem, but we cope. A stepstool like you mentioned is exactly what we use. A small, cheap $10 or $20 one is all you need and it can be stowed in a closet for travel. We also arrange the items in the cabinets based on frequency of use so as to not have to reach all the way to the top shelf every time. The more commonly used stuff goes on the first shelf in the cabinet or in drawers or cabinets under the sink. As Eric mentioned, you'll find most toyhaulers with tall rooflines. You just have to put a little time into some arranging your stuff and you'll be fine.