#4 Connie Comes to Town: Connie is newish in town and looking for part-time jobs. She was a waitress "last summer".
#29 Jack Davis' first appearance.
#31 Family Vacation Part 1: Jimmy Barclay's first appearance.
#34 Stormy Weather: "I'm fifteen, Mom!"
#50 Karen: Karen Crosby dies.
#54 Peace on Earth: The Barclays are robbed.
#84 The Battle, Part 2: The last time Hal Cunningham was confirmed alive.
#95: The Very Best of Friends: Karen died 'a year before'.
#99: The Visitors: The Barclays were robbed 'last year'.
#108 Isaac the Courageous: Rodney Rathbone is introduced. Lucy says that Rodney is "16 and still in middle school". Apparently she and the other protagonists are as well, so she's probably 11, or maybe 10 and a grade ahead.
#113 Suspicious Minds: Connie wants to buy a "brand new used car", and to use it she must be at least 16.
#114: The Big Broadcast: Lucy is introduced as "Lucy Schultz".
#133 Cousin Albert: Lucy is "in middle school".
#154 Coming of Age Jimmy enters adolescence.
#192 Jack Davis is driving.
#194 Connie teaches Eugene to drive.
#203 Jack Davis has a mustache and is a pizza delivery boy.
#204 Wonderworld: Lawrence Hodges is introduced.
#254: Katrina Shanks is introduced. She is a similar age to Eugene, and we can assume not too much older than Connie ("The Champ of the Camp, #583"). She's living away from her parents, so we can assume at this point she's at least 18.
#294: Stewart Reed Barclay is born.
#299 The Truth About Zachary: Lucy says that she was "9 when her dad (Hal Cunningham) was killed in a car accident".
#300 Eric Myers considers asking Donna out, and is apparently driving by this time, suggesting that Donna is probably about 15 to 16.
#308: Lawrence is an adolescent, and this is his last (regular) episode.
#323: June Kendall gets Connie a credit card, potentially implying that Connie was not eligible for one on her own.
#340 Pokenberry Falls, R.F.D: Stewart is a year old.
#351 What Are You Gonna Do with Your Life: Connie tries out different internships.
#375 The Pushover: Jared DeWhite and Sarah Pratchett are introduced; Sarah seems a bit younger than Jared.
#380 Connie needs just "one more class to graduate".
#385 Pokenberry Christmas: Stewart is old enough to hold conversations and try to learn to ride a bike.
#397: Mandy Straussberg is introduced and is wittle.
#398: Mandy is miraculously obviously older than in the previous episode — there's not really a good way to reconcile this; perhaps "Tornado" is set chronologically earlier than it appeared.
#405 Connie graduates as valedictorian, and can be assumed to be 18 at this point.
#443 Rodney is in high school… with Mandy Straussberg.
This would explain Connie sounding so different between Champ of the Camp and Connie Comes to Town. Also good timeline
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