If you like BIG projects, most of those are DIY, but some require a bit of experience !
The parts to do a COMPLETE front barke job, (rotors, ceramic pads, full hardware and hoses) would be well under $500 (online, RockAuto). Not difficult, but not really a job for first timers. At that age, the back brakes are likely no good either. Probably about the same for parts, but a bit more complicated.
While you are at it I highly recommend replacing all of the metal brake lines. Again, not hard (especially if you use NiCopp brake line), but not a job for first timers.
The fuel line would be a bit more DIY. There a a couple of videos on YouTube on how to replace steel fuel lines with nylon (skip the fancy press tool and just heat the tubing with boiling water to press on the fittings). Replace as much of the fuel line as possible without having to do additional splices.
The water damage could be the KILLER ! If there is rot in the walls, there is likely rot in the floor. Depending on how far the rot has gotten this could be the end.