Theme: We're not going to the mountains this year. - Three words, hidden in the themes, that indicate a vacation at the shore this year.
20A. Cultivated area with sloped sides : SUNKEN GARDEN
28A. Planet size calculation : SURFACE AREA. Odd clue.
44A. Birkenstock fastener : SANDAL STRAP. Some difference from the wing tips mentioned later.
52A. Summer getaway that characteristically has the three components hidden at the beginnings of 20-, 28- and 44-Across : BEACH HOLIDAY
Argyle here. Gareth did a good job following a tough act. Tough little boxes on either side with only one square entrances. 25 five letter words, 24 four letter words. Letter runs in the NW corner surprised me. The middle top and bottom have possible naticks.
Across:
1. Datebook sequence : MTWTF. Days of the week.
6. "__ left his home in Tucson, Arizona": Beatles lyric : JOJO. From the song, "Get Back", released in 1969 as a single. Info.
10. Bartender's measure : SHOT
14. Vowel sequence : AEIOU
15. "__ Ben Adhem" : ABOU. A link to the poem.
16. Way up there : HIGH
17. Basic principle : TENET
18. Nail polish layer : COAT
19. Prefix with China : INDO
23. Psychic's supposed skill : ESP
26. Stat for A-Rod : RBI
27. Number of stars, perhaps : RATING
32. Iron output : STEAM. For removing wrinkles.
33. Chuck wagon grub : CHOW
34. Aloe __ : VERA
38. See 56-Across : ARENA and 56-Across. With 38-Across, former name of the Sacramento Kings' home : ARCO. (Now known as the Power Balance Pavilion) (manufacturer of sports wristbands).
39. Ad __: for this special purpose : HOC
40. Traded punches : BOXED
41. Counterpart of 61-Down : YANG and 61-Down. Feminine force : YIN
42. Polio vaccine pioneer : SALK
43. Radical : ULTRA
46. Early Tenochtitlán citizens : AZTECS. Who? you might ask. Located on an island in Lake Texcoco, in the Valley of Mexico. map.
50. Minuscule amount : BIT
51. Critter in a colony : ANT
57. Object of worship : IDOL
58. Survive : GET BY
62. Any minute now : SOON
63. "Momma" cartoonist Lazarus : MELL. I recall someone linked Momma for us once.
64. Gestation sites : UTERI. Plural of uterus.
65. Standard Oil brand : ESSO. Exxon in the USA.
66. "My word!" : "I SAY!"
67. Tennessee footballer : TITAN. They are based in Nashville, LP Field. Name source.
Down:
1. Welcomer on the floor : MAT. Yeah, the floor of the porch, maybe.
2. Ball supporter : TEE. If you thought cup, get help. If you don't get my comment, bless you.
3. Break the tape : WIN
4. Wing tips' tips : TOEs. Wing tips are a fancy pair of men's shoes.
5. Space cartoon set in the year 3000 : FUTURAMA. Very strange characters.
6. "Rush Hour" co-star : JACKIE CHAN. Famous for doing his own stunts.
7. Orchestral reed : OBOE
8. "Blue Nights" writer Didion : JOAN. A memoir of the death of her daughter.
9. Got too big for : OUTGREW
10. Reckless gambler's loss? : SHIRT
11. Language of India : HINDI
12. Utah city : OGDEN. Wikipedia entry.
13. Skimpy swimwear : THONG
21. Network with a peacock : NBC
22. Motorists' org. : AAA. American Automobile Association
23. History test component : ESSAY
24. Kama __ : SUTRA
25. Get gussied up : PREEN
29. Tooth tended to by a vet, perhaps : FANG
30. "Get __ of yourself!" : A HOLD
31. Hybrid '50s musical genre : ROCKABILLY. Rockabilly Hall of Fame.
34. Bit of a shock? : VOLT
35. Like charges for new car options : EXTRA
36. Showed over : RERAN
37. Go with the flow : ADAPT
40. Laugh till it hurts : BUST A GUT
42. Sushi bar order : SASHIMI. but not sushi. Link.
44. MIT or NYU : SCH.
45. Tupperware topper : LID
46. Lower in esteem : ABASE
47. Goose eggs : ZEROs
48. Cantina order : TACOs
49. Cheap, in commercialese : ECONO
53. Laudatory poems : ODEs
54. Whatever she wants, she gets : LOLA
55. Himalayan legend : YETI
59. Asian New Year : TET
60. Cause of a tan line, perhaps : BRA. A final strange ?
Argyle