"un fol amour " and "de folles aventures" are often used in books and tends to be more literary, mostly because of the melody of the "liaison" (a consonant followed by a vowel is much more musical than two consonants : un amouR Fou, un foL Amour). Used when speaking to someone, it can be quite ironical, so be careful ;) !

It is all crazy ,no difference ;)

there isn't any difference of meaning but "fol" is not often used. People say more "un amour fou" Nevertheless you can use "folle" before or after: une folle aventure/ une aventure folle une folle histoire/ une histoire folle