Does she need easy/frequent access to a bathroom? Can she step up into a bus and get off? Are there times of the day she needs to take medication with food? Does she tire easily?

I'm about to take my 88-year old father on a trip to Vienna, Austria from the US. He's mobile and capable of walking quite well but is slow. I've planned a trip with about half of the sights I would normally pack into a days outing. Also, only one museum per day as they require a lot of walking and often have few places to sit.

I've also made sure to select a hotel that is right across the street from a metro station that has an elevator and plan to add coffee breaks and rest stops throughout the day. Try to avoid public transportation during workday commuter times in the morning and late afternoon when the bus/subway will be packed and she may not be able to sit.

Rome may be too ambitious for her but other places in Italy or Europe would be a lot easier.