Those kits look nice, but kinda spendy.
For a trail fix, I would just use basic push to connect parts from a vender like McMaster Carr. I would get:
1: tube fitting (6mm?) to male NPT, likely 1/8" NPT
2: Female NPT to female NPT coupling, likely 1/8" NPT
3: Schrader valve w/ 1/8" male NPT
4...