“I’ll Remember April” has been used by musicians as a "barn-burner" for many decades. It's smooth, half-time feeling melody makes it possible for the rhythm section to play VERY fast underneath if desired, and it's alternating Latin/Swing set-up gives the impression of a highly arranged composition while offering interesting possibilities for soloing. It's form is ABA with 3-16 bar sections, so it takes a little to internalize it compared to the very standard 32-bar form tunes. The A sections are half-Latin, half-Swing and the B section is all Swing. Geof Bradfield's contrafact offers a more active Bop-style melody line, inspiring the rhythm section into a more groove-based approach. While soloing with the tracks, it can be beneficial to imagine the tempo being much faster and try some simpler, less dense lines that make sense for this tempo but also might be applicable to faster tempos.
“I’ll Remember April” was recorded by Woody Herman and His Orchestra and entered the pop charts in 1942. With its long form, it wasn't seen as a great contender in the pop world, but there were a number of early recordings by singers like Bing Crosby before it crossed over as a jazz staple, with recordings by artists as varied as Ella Fitzgerald, Charles Mingus, and Keith Jarrett.