It depends a lot on how much work a person can do or will pay to have done. Some people want to change things a lot and will fix a lot so they buy trailer in bad condition for little money. Some people want trailer that they will not need to do any work on and can just buy and use. They pay more for trailer in better shape.
Fiber Glass walls and top can be fixed but to hide patch and make look good means whole thing must be painted.
Some cracks are just age, and do not matter, like wrinkles on person only skin deep.
Some cracks are from one time thing like rock from road hitting front or side. If it does not leak may not need to fix it.
Cracks where trailer sits on metal could mean whole trailer is falling down onto metal or metal is bending and hitting fiber. Not easy to fix and must be fixed. Or cracks where door hinge is you might have to fix so door does not fall
off. Or cracks that let water leak in you have to fix so floor does not rot.
Your english is better than I am able to do in any other language so good job of getting your message understood.