4. Hands down: BY FAR.
9. Syrup source: MAPLE. Not sure about this, surely "Maple Tree"? Maybe I'm being pedantic.
14. "There it is!": AHA!
15. Compact cosmetic: ROUGE. The "G" was my final fill, wasn't sure about the name crossing.
16. Build a new room, say: ADD ON.
17. "Da 5 Bloods" setting, for short: 'NAM.
20. Nutrition regimen: DIET.
22. North America's tallest peak: DENALI. 20,310 feet (or 20,320 depending on when you last looked it up). The mountain was re-measured in 2015 using improved measuring technology.
26. Hushes: SILENCES.
30. Vanity cases: EGOS.
32. Pt. of USNA: NAV. Seems an arbitrary abbreviation for "Navy", simply chopping off the last letter.
33. "Selma" director DuVernay: AVA.
34. "Selma" actor David: OYELOWO. Nice proximity of these two.
37. Small bird with a big voice: WREN.
42. Helgenberger of "CSI": MARG.
43. West Coast sch. whose application process may include an audition: CAL ARTS. A couple of friends of mine went to Cal Arts to study animation.
44. Break off: END.
45. Cynical start?: CEE. C for Cynic.
48. Epiphany trio: MAGI.
49. Finishes a gin rummy turn, e.g.: DISCARDS.
56. Aye-aye or dik-dik: ANIMAL. I knew dik-dik, but the other was new to me. I discover it is the world's largest nocturnal primate, and is a long-fingered lemur from Madagascar.
58. Flight board info: GATE.
64. No-frills bed: COT.
65. Slow tempo: LARGO.
66. Future esposa, perhaps: NOVIA. The bride, in Spanish.
67. Roxy Music name: ENO. Brian Eno, the legendary producer, ambient music component and ex glam rocker with Roxy Music. Seems like a good excuse for a music link. Eno is the guy with the long blond hair playing a very rudimentary synth.
69. Ridley of the "Star Wars" sequel trilogy: DAISY.
70. TV room: DEN.
Down:
1. Wedding __: BAND(B). The first of the "invisible" letter down entries. BANDB parses to B AND B by the way, took me a moment to see that.
2. Hindi word for "tea": CHAI(R).
3. Showed up: CAME(O).
4. Exclamation during a polar bear plunge: BRR.
5. "__ had one job!": YOU.
6. Endow: FUND.
7. Moorehead of "Bewitched": AGNES.
8. Restrain: REIN IN.
9. Bullet train technology: MAG-LEV.
10. Server's edge, in tennis: AD(M)IN.
11. Law enforcement org.: PD(A).
12. __ and behold: LO(T).
13. Dash used in date ranges: EN(E).
19. "The Lion King" lion: NALA.
21. Option in a classic paradoxical dilemma: THE EGG.
24. Wrinkled tangelo: UGLI.
25. Jennifer Egan's "A Visit From the __ Squad": GOON.
27. Web store icon: CAR(E)T.
28. 12/24 and 12/31: EVE(N)S.
29. __ Antonio: SAN(D).
31. Budget carrier HQ'd in Dallas: SWA. Southwest Airlines. They used to be fun to fly with when I first moved to the USA, now not so much, they've got much more corporate.
34. Muscat resident: OMANI.
35. Fabric measures: YARDS.
36. Tolkien monster: ORC.
37. Twist, as a wet rag: W(I)RING.
38. Cyberchatted with, briefly: IM'ED. Could be an IM, a PM or a DM.
39. Orange tuber: YAM.
40. __ of luxury: (F)LAP.
41. Number of candles, perhaps: (R)AGE.
45. Big name in cameras: CAN(Y)ON.
46. Actor Bana: ERIC.
47. Astronomer Halley: EDMOND. I knew the ED part, but flip-flopped between EDWARD and EDMUND before the cross rescued me.
50. Batting __: CA(D)GE.
51. South Pacific island group: SAMOA.
53. Finished perfectly: (P)ACED.
54. Musical pitch: (A)TONE.
55. Historic British school: (L)ETON. You'd think it was the only school in the UK if you went by crosswordese. It is quite historic, but the school in the town where I grew up, Winchester College, was founded in 1382, whereas Eton didn't come along until 1440. The King's School in Canterbury was founded in 597, so has both beaten by a good half a millenium.
57. __ Strauss & Co.: LEVI. I'm wearing a pair of Levi 511's today.
59. USN officer: (B)LT.
60. "How cute!": (U)AW. United Auto Workers union in case you're wondering.
61. Do, __, mi: (D)RE.
62. Knock: DIS.
63. "Huzzah!": YAY!