Electrical is gone

For the instrument lights, I'd go right to the headlight switch, pull it out where you can get to it.

There are three, actually 4 circuits in the switch

The HEADLIGHT switch section if fed 'unfused' as I mentioned earlier

The TAIL and PARK circuits are fed from the tail fuse, and this part of the power feed also provides power for the dash lights switch and dimmer, which then feeds off OUT of the switch to the instrument panel fuse

So in order for the dash lights to work, BOTH the tail light circuit has to be working, and the instrument circuit has to have continuity and have a good instrument fuse..

Some other things to suspect are the instrument cluster wire connector(s) which get corroded, the connector pins break loose from the board, and the copper board and lamp sockets get corroded.

This corrosion in the fuse panel is typical.