the second quote looks more down to earth, however are either quote fixed? i can see a quote of 35k spiralling.
you need to sit down with either garage and have a face to face discussion . decide levels of work and have definite break points. ie points where you can call a halt should money become a problem.
if it was me i always like to work from a solid base , so body corrosion first as this can easily explode cost wise.
point is .if you have a good mechanical side, you can work down, if the body is sound , you can work up , electrical is niether here nor there ( being a ret auto electrician helps) interior is last.
to me there is no point in spending money of electrical and mechanical if the body is going to cost silly money to repair, unless you are so attached that money is no object.
so from the second quote it sounds as if they are going to be looking at the electrical system , and mechanical to get the vehicle starting and running ,this alone could involve many hours of cleaning and repairing looms etc (rodents nest may be connected to non starting and electrical gremlins and they could most likely have chewed through a loom or two and stopped countless circuits). this again is a job which if you wanted to get your hands dirty you could probably tackle yourself (finding the damage and then replacing wires colour for colour till repaired, its not hard just time consuming and of course if paying a garage costly).
.