X Plane 11 steam purchase

I am planning to purchase X Plane 11 and Steam has a sale on now. However, I would prefer to not have it installed in the program files folder which is the default install location. However, it is my understanding that steam will only allow 1 steam library per drive label. I'm not a tech person so I don't want to attempt to partition my C drive. The only other alternative might be to put the game on an external drive I use for storing large amounts of data. However, I'm not sure that is a feasible option.

Does anyone have any ideas on what I might be able to do which is simple ?