When all things are considered, young adults of today live more satisfying lives than those of their parents, in my opinion.
这句话当中的“when all things are considered ”和“ in my opinion ”都显得多余。完全可以去掉。改为：Young adults of today live more satisfying lives than their parents.
Due to the fact that our grandparents were under an obligation to help their parents，they did not have the options that young people have at this point in time.
“ due to the fact that ”就是一个很典型的繁琐的表达方式的例子，可以替换，简化为下面的表达方式：Because our grandparents were obligated to help their parents, they did not have the options that young people have now.
The farm my grandfather grew up on was large in size.
large对一个farm来说就是size方面的large, 所以in size可以去掉，
改为：The farm my grandfather grew up on was large.更简洁的表达方式为：My grandfather grew up on a large farm.
My grandfather has said over and over again that he had to work on his parents' farm.
建议这里的over and over again 就可以改为repeatedly ，显得更为简洁：My grandfather has said repeatedly that he had to work on his parents' farm.
The situation that resulted in my grandfather's not being able to study engineering was that his father needed help on the farm.
从意思上来分析，上面这句话需要表达的重要的概念是“grandfather's not being able to study ”，而在表达这个概念时，原句用的主语是 situation ，谓语动词是 was ，不能强调需要表达的重点概念，
建议可以改为下面这句话：My grandfather couldn't study engineering because his father needed help on the farm.
2.避免频繁使用“there be ”结构，例如下面的句子：
There were 25 cows on the farm that my grandfather had to milk every day. It was hard work for my grandfather.
可以改为：My grandfather worked hard. He had to milk 25cows on the farm every day.更简洁的句式为：My grandfather worked hard milking 25 cows daily.
Dairy cows were raised on the farm, which was located100 kilometers from the nearest university and was in an area that was remote.
简介的表达方式为：The dairy farm was located in a remote area，100 kilometers to the nearest university.
In the fall, not only did the cows have to be milked，but also the hay was mowed and stacked by my grandfather's family.本句不够简洁的原因是本句的重心应该是“忙碌的家庭 -my grandfather's family ”，而使用了被动语态后，仿佛重心变成了 cows 和 hay 。下面的表达方式是主动语态，相对来说更简洁一些：In the fall，my grandfather's family not only milked the cow but also mowed and stacked the hay.
My grandfather didn't have time to stand around doing nothing with his school friends.
Stand around doing nothing 其实可以用一个动词来表达，即 loiter ：My grandfather didn't have time to loiter with his school friends.
Profits from the farm were not large. Sometimes they were too small to meet the expenses of running a farm. They were not sufficient to pay for a university degree.
两句话的信息可以合并为下面这句更为简洁的句子：Profits from the farm were sometimes too small to meet operational expenses，let alone pay for a university degree.