We've got your back. With the Tough-O-Meter, you'll know whether to bring extra layers or Swiss army knives as you summit the literary mountain. (10 = Toughest)
(2) Sea Level
Besides the fact that the book is set in San Francisco (it's at sea level), feel secure in knowing that even the most analog-devoted grandma will understand the ideas behind the technology after Marcus explains them.
Anything that might be unknown to readers—from mathematicians to prankster social protest movements—is briefly clarified and makes only you want to find out more. Doctorow's massively invested in ideas being accessible and people learning how to control their lives on their own terms. You'll keep turning pages just to find out what happens to Marcus next.