All at once(within 24hours) my only my driver window rolls down, my AC blower stopped working and my speedometer isn't working. I have a 2003 Toyota RAV4 prior to the blower dying my wife smelled burning plastic or rubber. Please help. I just would like to know where to start.

look under the dash for melting wires. often blower motor resistor wiring or assembly will melt from the heat they create making various fan speeds

Could that have an effect on my other issues? Like maybe they are all harnessed together?

yep, wiring faults can go like dominoes