I'm reading/working through this book now and can't recommend it enough, especially for those with limited time (or limited ability to focus and study due to environmental factors). I've worked through most of the first two chapters of SICP, but honestly felt a little overwhelmed at times. TLS has been enlightening AND fun. The format is genuinely unique and well-suited for reading/thinking in the small slivers of free time I have between work, kids, freelance, Khan academy, etc.

Most exercises don't require an interpreter, which is nice if you need a break from screentime. But I do enjoy working through some of them in Racket or even Pixie Scheme. TLS isn't free or available in a digital format (AFAIK), but the book is inexpensive and very portable.