A Handy Guide to the Hope Sherwood Episodes:
Episode #30, Original Airdate: October, 9, 1970 "The Slumber Caper" In this episode the girls get permission to hold a sleepover, much to the horror of the three boys who make plans to scare the girls with ghost stories and put itching powder in their sleeping bags. The plans are going well and the guests list is expanding (although oddly, no girls Cindy's age are invited, even though it is her party too) and includes guest stars Carolyn Reed as Karen, Barbara Henderson as Ruthie and Hope Sherwood as Jenny. However, things do not go smoothly. Marcia is soon forbidden from having the party because she receives detention! It seems like she has drawn an unflattering picture of her teacher, Mrs. Denton and scrawled under it "Mrs. Denton: A hippopotamus"! She denies writing the message, but admits to drawing a picture of.... George Washington (believe me, this is one unattractive teacher) and leaving it in her desk. The party is canceled until Mike talks to the principal and comes to his senses and decides to believe Marcia and let her have the party. Marcia, in the mean time, has decided it was her friend Jenny who wrote the message and un-invites her to the party. At the party, however, Patty reveals that she was the one who wrote the message and Marcia rushes to invite Jenny back over. And of course, at the end of the episode, Patty goes and tells the principal what happened so the good Brady name is restored.
The next Hope Sherwood episode (#65, "The Big Bet", original Airdate January 28, 1972) marks her first appearance as Greg's girlfriend, Rachel. In this one, Greg boasts that he can do twice as many chin-ups as Bobby can. Hurt, Bobby challenges Greg to a bet, and works out all week in preparation. When Greg loses, due in part to his lack of practice, he is forced to take Bobby along everywhere he goes, including a date at the drive in with the lovely Rachel. Of course, Bobby being who he is, makes a mess of the date, even going so far as to accidentally punch a hole through the top of the convertible with an umbrella.
Episode #89, "Greg Gets Grounded" (Original Airdate January 19, 1973) is a personal favorite of mine. In this episode, Hope Sherwood, reprising her role as Rachel goes on yet another date to the drive-in with Greg only to have things work out a little differently than planned. When Bobby lets it slip to Mom and Dad that Greg almost was in a car accident, because he was looking at a record while driving, they take away his car privileges, even though he wanted to go to a rock concert that weekend with Rachel. Greg then sees a loophole in what they said. They said he couldn't drive their car, not any car, so he goes and borrows a friends car. Mike doesn't like it, but he goes along with it and lets Greg drive the car to the drive-in with Rachel only to have a frog that was left in the car leap on her head, wrecking yet another romantic evening.
The final Hope Sherwood episode (#116 "The Hair-brained Scheme", Original Airdate March 8, 1974), is also the final one of the series. It is also the only episode that Robert Reed wasn't in (they didn't know it was going to be the final episode, and he had had a problem with the script and refused to be in the episode, even though the plot revolves around Greg's high school graduation and it made zero sense that he wouldn't be there for that). In this episode, Bobby tries to sell net and Natural Hair Tonic door to door with little results. In fact, Greg is the only one who actually buys and uses the product, to disastrous results: he hair turn orange. On his way to the beauty parlor with his mom, he runs into two girls he knows Gretchen (Hope Sherwood, apparently in the witness protection program, since she looks the same as she did as Rachel, but everyone calls her Gretchen) and Suzanne (Barbara Bernstein, Florence Henderson's daughter using her father's last name) much to his dismay. Of course my the end of the episode his hair is back to his normal chestnut brown.