Chernev's analysis is not the greatest. Yeah, many US masters of a certain age used Chernev. When you think of it that way, it's not such a ringing endorsement.
Go to your local library and check out Kasparov on My Great Predecessors. Start with volume 1. That will probably take ~4 months to really digest.
I've heard incredible things about Kasparov on My Great Predecessors. Thanks for reminding me. I should probably sit down with a real chess board and play through the games like that?
Where do you get the annoated games by Charousek, McDonnell, Morphy et al. on Chess Informant etc.? Is this something that requires a subscription?
Not annotated.
I got the Charousek games from chessgames.com, which has more than ChessBase. I used ChessBase for McDonnell and annotated them myself (you'll find them on my blog). I have several books on Morphy with annotations of some of the games.
I've spent hundreds of dollars on Chess Informant products, and also won 500 Euros worth through a contest.