puzzle

 ACROSS

  1 Bit of bounce

  4 They're in charge (think "top")

  8 "I'm outta here!"

 13 One might propel a lifeboat

 14 Puma competitor

 15 ___ E. Neuman

 16 Point where good momentum stops, in football ("forward")

 18 Alternative to an exchange

 19 Sends romantic signals

 20 Doomsday for Caesar

 21 Stick up for

 23 Dishwasher soap brand

 26 All tied up

 27 Choose to take part

 30 Typical young adult novel reader

 31 Green, in Granada

 33 French ___ (big instruments)

 35 Dr.'s field

 36 Heartland residents ("Middle")

 39 ___ choy

 42 Tiny

 43 Enticed

 47 Some raggedy dolls

 49 Braying bunch

 51 Roberts of romance

 52 Gymnast's performance

 54 Got class credit

 56 Countess Grantham on "Downton Abbey"

 57 Oscar winner Matlin

 59 Loosen up on the massage table

 61 Senior homeowner's cash source ("reverse")

 64 Greek moon goddess

 65 Opera highlight

 66 Dot-com or #MeToo

 67 ___ so often

 68 Final financial figure ("bottom")

 69 Lawn droplets

DOWN

  1 Part of a Rice Krispies trio

  2 Kernel holder

  3 Suggest, as a solution

  4 "Splish Splash" singer Bobby

  5 Go too far with

  6 Crux

  7 Back talk

  8 Downhill coasters

  9 Cause's follow-up

 10 Show your worth ("up")

 11 Kyoto cash

 12 Throw in

 15 Huffington with a "Post"

 17 Actress/former Parliament member Jackson

 21 App coder, slangily

 22 Night of anticipation

 23 Ring shape

 24 Don't start?

 25 London setting of "Call the Midwife" ("East")

 28 Expression that's coined

 29 Works up a sweat

 32 Ambulance initials

 34 Show with Ego Nwodim and Chris Redd, briefly

 37 Give forth

 38 End-of-day photo op

 39 Conference without the jury ("side")

 40 Peace activist Yoko

 41 Work hard ("down")

 44 Snow-White's sibling

 45 Prior to, poetically

 46 One honored in June

 48 Person opposed to weed control?

 50 Injury you may ice

 53 Proofreader introducing an error, e.g.

 55 Birdbath buildup

 57 Ground-up corn

 58 Prefix for "cultural"

 59 Find a purpose for

 60 Calif. neighbor

 62 Calif. neighbor

 63 Wide-open mouth

solution