Puzzle

 ACROSS

  1 Pet adoption org.

  5 Dog's fur

  9 50/50 quiz answer

 14 From Bangkok, say

 15 Solo at the Met

 16 Big petting-zoo animal

 17 Thanksgiving staples (circle letters 2-4!)

 18 Highway hauler

 19 Certain saxophones

 20 No. on a business card (letters 1-3)

 21 Valiant effort

 23 Headey of "Game of Thrones"

 25 24/7 med. facilities

 26 Creator of Atticus Finch

 27 Expired

 29 Boot bottoms

 31 "Xanadu" rockers, briefly

 32 The Minotaur, e.g.

 34 Inside look? (letters 3-5)

 38 Thumbs-downs

 39 Consume

 40 Inspired poem

 42 Words before "break" or "tear" (letters 1-3)

 43 Real bargain

 45 Aired again

 47 10, in dates: Abbr.

 48 Gal in "Wonder Woman"

 50 They're printed on books' spines

 52 "___ sells seashells ..."

 54 Roughly, informally

 55 Laptop brand

 56 Average guy, and a clue to the starts of 21-Across, 3-Down and 35-Down

 59 Consume

 61 Far from fitting

 62 Omaha stake

 63 Barbershop sound

 65 Rural skyline sights

 66 Senator Booker

 67 USC's archrival

 68 Scrumptious

 69 Building additions

 70 Cry after a close call

DOWN

  1 Messy room

  2 Excellent, in '90s slang

  3 You bend over backward to do it

  4 Ushers' paths

  5 Goes through a chain reaction

  6 Shake cookie

  7 Without a goal (letters 3-5)

  8 Component on a chopper's rear (letters 3-5)

  9 Mark as important

 10 Everything but the last resort

 11 ___ art (barista's creation)

 12 Campfire treat

 13 "Settle down now"

 22 Subj. with conversation practice

 24 Interstellar cloud

 27 Bender of light

 28 Loads and loads

 30 Like paradise

 33 Soaring business?

 35 Doritos flavor in a blue bag

 36 ___ bitten, twice shy

 37 Chinese Zodiac rodents

 41 Secrets to cracking some codes

 44 Skin cream target

 46 Common biofuel

 49 Reformer Dorothea

 51 Prepares to swing

 52 Sotomayor of the Court

 53 Recovers

 56 Barely

 57 Teeny

 58 ___+Z (undo, on a PC)

 60 Z is a valuable one in Scrabble

 64 Rabbit's foot

Solution