We all know how the movies happen at the end of Back to the Future, Part II and the beginning of Part III. Western Union delivers it at some road next to a sign for future housing development. Marty McFly receives the letter dated 70 years prior.
Why would Doc take such a big unnecessary risk? Why not simply order the delivery to his own house at that date in 1955?
It makes sense that Marty would make the logical decision to go back to 35-year-old Doc Brown to help him.