Is it needed to run, no. Is it needed to not pollute the environment, yes. This is where your state laws come into to play. In Oregon you can not mess with emission equipment period (in other words no exhaust shop, even in the sticks will cut your cats off and straight pipe your ride) and in DEQ areas 76-up get the every two year sniffer. Now, my 79 F-150 with a built 460 would pass with high flow cats and a good tune.
In your case, leave all the evaporative emission equipment intact and functional. Gasoline vapors are toxic, flammable, and there goes your fuel (you just paid for) while drawing moisture and degrading its quality. Exhaust emission just need a good 3 way, 400 cell cat with an exhaust routed the way the factory did and you and your passengers will enjoy not smelling like raw exhaust and wondering why you all have headaches. Follow it all up with a good tune and your golden. This assumes you have a healthy engine.
With a good schematic, coming to understand the evaporative emissions probably isn't all that difficult, its just plumbing in the end.
