I used Elemental science Earth Science and Astronomy logic stage with my then 6th grader, It is straightforward, and he really learned a lot. We did add in videos and alternate books as we found them.
As for the writing, yes that can be overwhelming. However, you do not need to assign all of it. For example, when the child is supposed to either outline or summarize the readings, you could do that orally. I would suggest writing down the answers to the discussion questions so they will have a study guide for the tests - if you will use them. We found the tests to be fair - required review and some studying, without being overwhelming.
The vocab words - only a few are assigned each week. you could make flash cards out of them
We generally did it 2 - 3 days a week. Day one was experiment day. Most supplies were easy to get, or I already had. On average, this day took the longest, about an hour.
Day two he would do the readings and outline, and discuss. Day three, he would do vocab, dates and sketch (sometimes he did these on days one and two). As well as any additional readings.
Oh, and we used the pdfs Though I love the look of the books!
Yes we enjoyed it. And recommend it.