Seems like a viable idea,but you still may have to do the sills and floors and possibly more depending on the extent of the rust,windows can be rusty after removing glass.The price of the flairs could exceed the repairs to the fenders.OH almost forgot the big wheels you will need to fill out the flairs will be expensive to.As for future generations,they can always return it to original if they want,if you scrap it,its gone for good.Its going to cost either way,do it if you want but i dont think it will save you any money in the long run,but i dont know enough about the cars condition to say for sure.