ACROSS

 1 Had upward mobility?

 5 Change with the scenery

10 Old TV show set in Korea

14 Minute quantity

15 Beach towel material

16 ___ mater

17 Slash mark?

18 Wiser partner

19 They may get stepped on

20 "Rough ride ahead!"

23 Attest

24 It's fit for a queen

25 Engaged in banter

28 Goat seen on treks

30 "No" voter

31 Shipwreck locator

33 History-book chapter

36 "Don't get so excited!"

40 Prophetic gift, for short

41 Stave off

42 Group of troops, collectively

43 "Begone!"

44 Shortcuts for ships

46 Geologic time period

49 Narrow groove

51 "Get ready for hard times"

57 Roll call reply

58 Waterproof coverings

59 Butter look-alike

60 Tabloid twosome

61 Dressing dispenser

62 It dissolved in December 1991

63 Docket item

64 Promotes heavily

65 It might have a lot of problems

DOWN

 1 They're cold-blooded

 2 Unhinged

 3 "Just to name a few" abbr.

 4 Custody

 5 Made amends

 6 Mouth formation

 7 Extreme passion

 8 Fly, to a spider

 9 Neophyte

10 Keanu Reeves film (with The)

11 "Hello" or "Goodbye"

12 Bit of mudslinging

13 "___ la vista, baby!"

21 Verb in IOU

22 Organs males lack

25 Raging Bull pugilist LaMotta

26 Small Federal Reserve notes

27 Procedure part

28 "Meet Me ___ Louis"

29 "___! Humbug!"

31 Animal fat

32 "Bobby Hockey"

33 Volcano in Sicily

34 Muddy, as water

35 Pesticide targets, at times

37 America's Cup entrant

38 Eggs, scientifically

39 Quick, open-topped automobile

43 Deceitful plan

44 Pizza party leftovers

45 Common inhalant

46 Body of moral values

47 Madonna-and-child sculpture

48 Bedtime story baddies

49 Flapjacks topper

50 Lightweight helmet, in India

52 Use acid to make art

53 Hardly any

54 Add-on to an if-then statement

55 Not so much

56 Civil wrong

57 "Boo" follower, in a triumphant shout