upgraded duster alt, no gas gauge, coolant temp gauge, wipers, or dome light

You need to do some testing rather than "throwing parts" (ignition switch, etc) at the problem

You can access three important points---

the IGN switch connector coming down from the column

the bulkhead connector, which you can probe from the outside

and of course test points under the hood.

Your ignition switch has several SEPARATE switches inside the container that is the swtich

You have the accessories switch, which is hot in RUN and ACCESSORY, and supplies the ACC buss in the fuse box

The IGN RUN (IGN 1) which comes out of the switch on DARK BLUE, and supplies the gauges and warning lights, goes through the bulkhead and supplies the ignition system and alternator field, regulator

The START (YELLOW) wire, hot ONLY in start, goes DIRECTLY from the IGN switch, through the bulkhead, to the start relay

The BALLAST BYPASS (BROWN) hot only in start, goes directly from the IGN switch, through the bulkhead, to the coil+ side of the ballast resistor

You should be able to clip your meter on the yellow "push on" at the star relay and determine if there is joltage there "in start." If not, check the bulkhead, and the IGN switch connector

If you DO have voltage, the problem is the start relay, or the Neutral safety switch, IE on the engine side of the firewall.

You should be able to check the brown bypass by clipping your voltmeter to the coil+ terminal, and should have battery voltage "in start."