Theme: Add a Word - A reveal word is added to the start (or left) of the start of the target word.
17A. *Pest-control device : MOUSETRAP. Field mouse.
25A. *Off-the-wall game? : HANDBALL. Field hand (on the farm).
30A. *Simple garment : HOUSEDRESS. Fieldhouse or field house, is a common name for indoor sports arena.)
44A. *One given to flights of fancy : DAYDREAMER. Field day. A sports day for the younger school kids.
49A. *Hidden explosives activator : TRIPWIRE. Field trip. Taking a class to an off-school venue.
64A. Figuratively, where some wild ideas come out of; literally, a hint to a word and its position when paired with the starts of the answers to starred clues : LEFT FIELD
Argyle here. And March, whether like a lamb of a lion, please leave. Conventional grid supports a 6-entry puzzle medium length fill. Hopefully with no nits.
1. Dash gauge : TACH. (dashboard/tachometer)
5. Pawn at a shop : HOCK. Apparently from Dutch hok, "prison".
9. Vague shapes : BLOBS
14. Height: Pref. : ACRO. Think acrobat.
15. Saintly glow : AURA
16. Sportscast rundown : RECAP
19. Hersey's bell town : ADANO. A 1944 novel by John Hersey that will live forever in crosswords.
20. Like paradise : EDENIC
21. Go round and round : SPIN
23. "Tao Te Ching" poet __-tzu : LAO
24. "Yummy!" : "DELISH!"
27. Grant-granting gp. : NEA. (National Endowment for the Arts)
29. Soul automaker : KIA
36. Aerobic exercise aid : STEP
40. Woodlands man-goat : SATYR
41. Campus URL suffix : .EDU (education)
42. Serious : GRAVE
43. Old Russian ruler : TSAR
46. Short-lived Egypt-Syr. alliance : UAR. (United Arab Republic)
48. Drunkard : SOT
54. Overthrow : TOPPLE
59. Farm female : HEN
60. "__ o' your throats": "Measure for Measure" : A POX. The nearly identical quote from The Tempest is more famous.
61. Phobic : AFRAID
62. "Alas and __!" : ALACK
66. In need of a chill pill : TENSE
67. Mystery writer Gardner : ERLE. Perry Mason - Erle Stanley Gardner
68. Colombian city : CALI
69. Beer holder : STEIN
70. Ear piece? : STUD
71. __-slapper : KNEE
1. Got under control : TAMED
2. Words after "crack" or "live by" : A CODE
3. Pitiless : CRUEL
4. Mubarak of Egypt : HOSNI. President of Egypt from 1981 to 2011.
5. Came out of one's shell? : HATCHED. Literally.
6. "Days of __ Lives" : OUR
7. Attend uninvited : CRASH
8. Letter after iota : KAPPA
9. Chastain of women's soccer : BRANDI
10. Guided : LED
11. City NW of Orlando : OCALA. Déjà vu ... again.
12. Unoriginal : BANAL
13. Thread dispenser : SPOOL
18. Ex-Disney CEO Michael : EISNER
22. Printer cartridge contents : INKS
26. Iraqi port : BASRA. Basra is roughly 110 km (68 mi) from the Persian Gulf and does not have deep water access but is still its main port.
28. Neighborhood : AREA
30. FDR's last vice president : HST. (Franklin Delano Roosevelt/Harry S. Truman)
31. Western defense gp. : OAS. The Organization of American States was founded in 1948.
32. Actress Hagen : UTA
33. IHOP condiment : SYRUP. The maple syrup season is running late this year. Go figure.
34. Ice cream maker Joseph : EDY
35. Brewski : SUDS. Slang.
37. Bagpiper's topper : TAM. For whatever reason, Google Images show few bagpipers wearing the Tam O'Shanter.
38. December 24 or 31 : EVE
39. Each : PER
42. Exit the bus : GET OFF
44. Tap concern : DRIP
45. Went round and round : ROTATED
47. Greet the day : AWAKEN
49. "__ Life": Sinatra hit : THAT'S
50. Rented again : RELET
51. Silly : INANE
52. Romeo and Juliet, e.g. : ROLES
53. Apply, as pressure : EXERT
55. Puncture with a pin : PRICK. Hand up for BURST.
56. Song of praise : PAEAN
57. City in northern France : LILLE. Wiki link
58. Comic Izzard : EDDIE. Eddie Izzard-Lord of the Rings & Pipes Link(9:20)
63. TV forensic drama : CSI. (Crime Scene Investigation)
65. __ shot : FLU