This article is from the rec.arts.sf.movies FAQ, by Evelyn C. Leeper firstname.lastname@example.org with numerous contributions by others.
Apparently, the makers of this film (Stephen Spielberg & Robert
Zemeckis) did all kinds of cute things, playing with the names of some
of the characters and with issues of time travel. Some of these are:
a) The mall where Marty McFly (Michael J. Fox) meets Dr. Brown
(Christopher Lloyd) for their time travel experiment is called the
Twin Pines Mall. Dr. Brown comments that ol' farmer Peabody used
to own all of the land, and he grew pines there. When Marty goes
back in time, he runs over and knocks down a pine tree. When he
comes back to the mall at the end of the film (BACK TO THE FUTURE)
the sign at the mall now identifies the mall as the Lone Pine Mall,
reflecting the fact that Marty had changed the present (1985) by
his trip to the past (1955).
b) Farmer Peabody's son is named Sherman. Sherman was the name of
the little boy time traveler in one segment of Jay Ward's cartoon
show, "The Rocky & Bullwinkle Show." The dog who owned his time
machine was named (surprise) Mr. Peabody.
c) On Marty's return to 1985 at the end of Part III, we see that
the ravine where the railway dead-ended in 1885 was the Eastwood
Ravine -- obviously named for "Clint Eastwood", the name Marty had
been using in 1885.