If you want to used barbed fittings I hope you have a camp stove you can have a pan of boiling water handy, as that is about the only way you'll get the line on over the barbs
I used 11/32 rubber fuel injection hose to make the connections so fittings didn't limit the ID of the nylon line.
Using a lighter you can gently heat the end of the nylon line and it creates a rounded bead on the end, then I ran the tips of my needle nose pliers around the inside of the line as it cooled to open up a little more ID on the ends.
Basically just used the rubber line for the joints and the nylon for the long runs under the car.