Goofs

When Elliot returns to the motel after sliding/playing in the mud, his clothes are clean and dry.

When Mike and Tisha first arrive at the El Monaco, Tisha is carrying her dog in a tote bag, but as they are walking around checking out the property, she's carrying the dog in her arms and the handbag is gone.

Arlo Guthrie was heard singing "Coming Into Los Angeles" in daylight. When the 1969 Woodstock concert first took place, Arlo came on stage at midnight right after Melanie.

When they are going to the concert we hear Melanie singing "Beautiful People" and it is daylight. Melanie actually performed at 11:00 PM when it was dark.

Billy talks about beating Monticello High School and catching three touchdown passes. Monticello High School had no football team at that time nor did it have one for decades before the festival. Also, if Billy was from White Lake or Bethel, he would have attended Monticello High School and would not have been playing against them.

In at least a couple of scenes with Elliot walking around the side of the hotel, you can clearly see a NID or Telephone Network Box. Almost everyone has them on the side of their houses now, but these weren't in use until many years later.

The song "Maggie M'Gill" by The Doors was used in one of the scenes. It was not released until 1970 and appeared on the album "Morrison Hotel".

One of the production staff refers to the Hog Farm commune leader Hugh Romney as "Wavy Gravy". By his own account, Romney was not given this nickname until about a month after Woodstock at the Texas Pop Festival (supposedly by BB King).

The attitudes about Elliot's being gay were those of the 21st century, not the late 1960s setting of the film. Even liberal people of that era were often offended or disgusted by homosexuality and they would have been unlikely to restrain themselves from expressing those emotions to people or in general.

In the cleanup scene, the Boy Scouts' uniforms have green socks with red tops. In 1969, Boy Scouts wore solid green socks.

Elliot says that he can sense his mother's thanks by the way she looks at him with only her left eye. He demonstrates using his right eye.