From where exactly will you start walking? The parking lot or bus stop below the Detached Palace? I will assume so.From the parking lot/bus stop it is a short ascent to the hill on which the palace building and park is located. I imagine it to be tiring for elderly people who are not good on their legs, but no problem for anybody else. I think there are some stairs involved, although I imagine that there is also a slope alternative.
The distance from the detached palace to the checkpoint is only 500 meters and all downhill. No problem except for those who have major problems with walking even shorter distances. Again, there are some stairs involved, but I believe there is also a slope alternative.