red vacuum cap is for your idle control (pretty sure) which is the thing with the shiny pipe a pic or 2 down. One side goes into the plenum/or just stick a small breather filter over it if running open quads, and the other in to the manifold (red cap)
Fuel in is at the rear of the manifold with a shitty fwd fitting that doesn't work to well in rwd applications, best to fuck it off and get a new straight banjo type fitting.
Fuel out is at the rear underneath the quads - the solid line that runs from the front where the rubber hose joins from the fuel pressure reg.
I think that's right, if you run heater hoses at the rear it becomes a lot more cramped as everything is at the back of the manifold basically....... I dropped the idea of having a heater in favor of a neater and easier to set up engine