I wish I had a book to recommend on canna-chemistry, but unfortunately this is a new field and good books take a long time.
Me personally, I paid some fine folks at a private university way way too much money to teach me forensic science, which led me to chemistry itself, and finally organic chemistry. community college is what the smart people do 
co2 will extract your compounds of interest, and a skilled operator on a good co2 system will know how to keep it from extracting things you dont want, or be able to separate impurities with ease. no worries about solvent either.