OK here goes:
That chassis should have a Delco 12SI. Identifiable because it has a flat disc fan not a sharp blade steel fan.
1) Which fuses blew? Chassis or house?
We need to move along so let's do this:
2) Grab a 12 volt test light the kind with a point.
3) Touch the alternator battery terminal. Does tester light?
4) If no light follow alt bat wire. Look for a square finned box with 3 bolts and heavy gauge wires bolted to it - a battery isolator.
5) We have to find out before going further.
6) The further along we get the faster the process becomes.
7) Other ways of doing this are a waste of time. Do it like a pro :)
Will proceed upon reading your report. Keep test light handy.