Treasure Island - pure gold. Kidnapped - gold.
I recall in the introduction to one of them he explains he wrote these stories for boys. Adventure, danger, fun characters. If you have sons you'll know there is a certain aesthetic young boy love and these books deliver it.
I also was amazed how much I enjoyed his books for adults, like the one about being on a ship as a kid (can't find the name).
If you look into his biography you find some really hard things that I guess he transformed into writing.