Honestly, the first book is a straight up mystery story that doesn't get really crazy and takes place in current times. That one seems like the easiest to film as it's almost just a buddy cop story with a scientist and hot headed detective

The 2nd and 3rd book though are just full of huge scifi set pieces and theoretical concepts that I had a hard time fully visualizing. They're just chock full of stuff that would need to be CGI to show.