Theme: Cozy Accommodations - Usually in a private residence.
17A. Comfortable indoor setting : ROOM TEMPERATURE
26A. "Wait, I'm not done ..." : "AND ANOTHER THING ..."
43A. Corporate oversight group : BOARD OF TRUSTEES
57. Guesthouse where one would enjoy the starts of the three longest answers : BED AND BREAKFAST
Argyle here. First, fantastic grid spanners and some interesting fill. "Board", in the past, would indicate all meals, not just breakfast. I think you can find B & Bs that do offer meals now.
Unfortunately, many a young couple have bought an old house that they thought would pay for itself by running a bed and breakfast. It's not that easy.
If you ever come to see me, I have a friend with an excellent B & B. Link.
Across:
1. Award sewn on a sash : BADGE. On a Scout sash.
6. Froth in a mug : HEAD
10. Frat party empties : KEGS. These two paired up nicely.
14. Assumed name : ALIAS
15. Italian wine site : ASTI. Map and it isn't the square island, Desper-otto.
16. Hacker's cry of success : "I'M IN!". Computer hacker, unlike the one in 23-Across.
20. Adjust for pitch : TUNE
21. Globetrotting reporter Nellie : BLY. She may have stayed at a bed and breakfast.
22. Struggle : TUSSLE
23. Links "Heads up!" : "FORE!"
25. Out of __: discordant : SYNC
33. Prepare for winter takeoff : DEICE
34. Divisions of history : ERAs
35. Actress Vardalos : NIA. Image. She starred in "My Big Fat Greek Wedding".
36. Serenade accompaniment : LUTE
37. "Need __?": "Hop in!" : A LIFT
39. Pablo Neruda works : ODEs. Chilean poet.
40. Drive up the wall, so to speak : IRK
41. Rental car option : AVIS
42. Flavor enhancer : SPICE
47. Sotto __: softly : VOCE
48. "Ah! Say no more" : "I SEE!"
49. Spiritualist Deepak : CHOPRA. I'm not familiar with him, so I read a little and I will say no more.
52. Agt.'s cut : PCT. (agent/percentage)
53. Forest females : DOEs
60. Persian Gulf prince : EMIR
61. "House" actor Epps : OMAR. Just two episodes left, the series ends on Monday, May 21.
62. Must, informally : GOTTA
63. Ice Follies venue : RINK
64. Virtual people, in a popular game series : SIMS. So far, I've resisted getting sucked into any of the SIMS games. Do we have any players?
65. William Jennings __, three-time presidential candidate : BRYAN. He ran against William McKinley in 1896, Theodore Roosevelt in 1900, and William Howard Taft in 1908.
Down:
1. 10-year-old Simpson : BART. His family is on the Fox network.
2. 2000s Giants manager Felipe : ALOU. He and his brothers are from the Dominican Republic.
3. Pop diva Celine : DION. She is from a large family in Charlemagne, Quebec.
4. Competitive demeanor : GAME FACE
5. Approx. figure : EST. (estimate)
6. "Get thee to a nunnery" speaker : HAMLET
7. Catch a glimpse of : ESPY. At the ESPN awards show, you might espy an ESPY.
8. Broke bread : ATE
9. Epithet never actually used by Cagney : "DIRTY RAT!"
10. Lowbrow trinkets : KITSCH
11. Aussie hatchlings : EMUs
12. Young lady : GIRL
13. Dagger of yore : SNEE
18. Iberian river : EBRO. The origin of the River Ebro’s name and map.
19. Family tree members : AUNTS
24. __-eyed jack : ONE
25. Medieval tenant farmer : SERF
26. Wing it, speechwise : AD LIB
27. Surgical opening? : NEURO
28. "Iron Mike" of football : DITKA
29. Crook's caper : HEIST
30. Non-studio flick : INDIE. Indicates it's from an independent producer.
31. Family tree member : NIECE
32. Neon and xenon, for two : GASES
37. Guacamole makings : AVOCADOS
38. Biographical span : LIFE
39. Selected : OPTED FOR
41. Sew sequins on, say : ADORN
42. Chicago-to-Miami dir. : SSE
44. KOA facility : RV PARK. (Kampgrounds of America, Inc.)
45. Kitchen cutters : RICERS. "Where do the blades go?"
46. Netmen's org. : USTA. United States Tennis Association (but it sure looks Spanish)
49. Trucker's "good buddy" : CB'er
50. Half: Pref. : HEMI
51. Norse god of war : ODIN
52. Bristol baby buggy : PRAM
54. Like some high-fiber cereal : OATY. The NYT crosswords use it but few dictionaries do.
55. SeƱora's "this" : ESTA
56. Jazzman Getz : STAN
58. ASCAP counterpart : BMI. (Broadcast Music, Inc.)
59. Cold War spy org. : KGB. (something)
Argyle