I'm not sure if this idea is going to help, but here goes...
If your ice cream cart is something you can transport to different places, why not offer these for parties? Like the Pritchon, or the chocolate fountain business.
Gawa ka ng party packages, tapos i-cater mo yung ice cream mo sa kiddie parties. I remeber when I was kid, there was this party which I found so cool (I was about 6 yata) because they wer giving out free "dirty" ice cream from the mamang sorbetero.
Ang downside nito, sasabihin ng parents, pde namang bumili ng gallon gallon nalang ng Magnolia... BUT, iba kasi yung dating ng "mamang sorbetero" type na ice cream eh.
Ewan ko lang kung magcliclick yang idea na yan...