Where to get close up to the original construction of the Great Wall at a low level.

What is the elevation of Jiayuguan City and can you see the unreconstructed remains of the original wall from there? I know the maximum height of the fort and it is too high for us oldies with health problems.

If it cannot be seen from the city, can anyone suggest where along the wall it can be seen at a lower level? We will be based in Zhengzhou city.