It is awesome that your son wants to spend time with you. But I also think a 14 year old is old enough to understand that you don't want to go on a long trip with his mother and her new husband.
This trip is just one thing, maybe discuss other things you can do after the trip with just the two of you.
I work to have money for shelter and food and, just as importantly, some spending money for hobbies and travel. The freedom to be able to drive basically anywhere any time is a great thing to have.
The inequalities today are large but also the standard of living for even the lower class is probably higher than any other time in history. You can go your entire life without holding a shovel or hammer or piece of firewood Imagine instead having to build your own house, grow your own food, and cut firewood to stay warm. Things aren't so bad.