The majority of the vacuum lines are ancillary control lines for emissions etc. Here is a manual diagram for the vacuum line routing. Seeming your truck is running all these lines and you've mentioned carbie woes, your engine isn't a 4G64 (the 2.4 is EFI, so you most likely have a G63B 2.0). Not going to make a difference in diagnosing the fault. There could be a number of issues with it not running - wrong fuel line orientation (the 2 fuel lines coming out of the pump have been crossed over, resulting in insufficient fuel delivery to the fuel bowl), a bad fuel filter (clogged), fuel pump is toast (not enough pressure), ignition timing screwed up (too much advance/retard), a bad coil, carb is dead (needs strip down and rebuild - this is not a job for carb noobs as the Mikuni is a biatch to work on...) The Mikuni itself has common faults from age/wear and tear that will straight up nerf performance - main culprits are accelerator enrichment pump (symptom is a flat spot on opening the throttle) and secondary vac actuator (no power from mid throttle upwards). Some of the parts are either difficult or to source or are NLA (choke wax pellet is absurdly hard to find and even harder to install)