I love Donovan's version- he plays it in G. He starts out with a neat little run that starts on the second string open and runs down into the G chord. Then the progression is as follows: G-Em-C-D (X2), then C-D, C-D, then G-Em-C-D, then C-D, C-D, then G-Em-C-D. Now you're at "Then one day sadness came....", which is G-Bm, G-Bm, G-Bm-Am. Next is Am-Em (X4), leading you to "...Then one day they met again...", which is G-Em (X2), then G-Em-C-F-D. The final line is G-Em, G-Em, G-Em-C-D (and the last word is sung over the little run that he began with, resolving on the G chord. It's fairly straightforward- you should be able to play along with the record/CD after a few practice runs.