Thats a good question. Kajukenbo being a mixed art is perfect for blending with others. Myself coming from Kajukenbo Kenpo branch from 91' I look toward systems that work in real self defense situations.
I started Brazilian Juijitsu in 95' after sparring with a Gracie Representitive and being choked and arm/lock with ease plus watching a skinny Royce gracie beat a Big wrestler named Dan Severn in UFC.
Being that Ju branch was part of Kajukenbo I thought it was only logical to strenghten that side. It addition Sigung John Bishop wrote an article called battle of the arts "Kajukenbo vs. Gracie Juijitsu." I thought perfect just blend it.
It worked great BJJ helped my training in Kajukenbo greatly and introduced me to Alive training concept which increased my confidence in handling myself.
Next was strengthing the BO branch with American Boxing/ Muay thai for striking. Again alive training against an uncoopertive opponent
Finally Villibrille Kali/dog brothers style stick fighting. for sticks and knife fighting ;simplicity which Sigung Gelinas can attest to and again part of the alive concept .
I read a lot of concepts from straightblast gym and trained with martial athletes like Egan Inoue, Matt thornton, Frank shamrock, Murillo Bustamante etc..which gave good insights on martial combat science
To be well rounded you need a:
Striking game: Muay thai, boxing etc..
Clinch Game: Muay thai(plum), Greco Roman clinching(real trapping)
Ground Game: Brazillian Juijitsu,
Self Defense street: Kajukenbo self defense
Weapons: Kali, Escrima, Silat,