Theme: Enough to make your head spin. - The sets of four circles are in the four corners spelling out DOOR.
49A. Hotel entrance, often, and, literally, what each set of four puzzle 35-Across contains : REVOLVING DOOR
23A. How a 49-Across goes : ROUND AND ROUND
35A. Paths described when things go 23-Across : CIRCLES
Argyle herereh elygrA. Quite the go-around. Note how the D revolves to be in the four corners so as to make a complete revolution. The reveal may have led to some head-scratching, I dare say, especially if you're missing the circles because the clue doesn't seem very clear.
Across:
1. Rope-a-__: Ali boxing style : DOPE
5. French wine valley : LOIRE
10. Tough : HARD
14. Agile deer : ROEs
15. Widish computer key : ENTER
16. "Typee" sequel : "OMOO"
17. Craggy outcroppings : TORs
18. Fielder's gear : GLOVE. (baseball)
19. Goes down in the west : SETS. The action, not the thing.
20. Nautical distance unit : SEA MILE. 1,852 metres(about 6,076 feet).
22. Twyla Tharp forte : DANCE. Wiki link
26. Weaver turned into a spider by Athena : ARACHNE. Spiders are the largest order of arachnids.
27. Zodiac division : SIGN
28. Roping and riding contest : RODEO
29. Daddies : PAs
30. Height: Pref. : ACRO. From Ancient Greek for “highest, at the extremity”.
34. L.A.-to-N.Y. direction : ENE
39. Rowing need : OAR
40. Flag maker Betsy : ROSS
42. Bon __: quip : MOT
43. Much of Santa's mail : LISTS
45. Big name in hair trimmers : WAHL. Not on many lists.
47. Marshmallowy treat : MOON PIE
51. Actress Kelly of "The Cutting Edge" : MOIRA. (Moira Kelly)
53. Earns : TAKES IN
54. Airing, as a miniseries : ON TV
55. Some plum tomatoes : ROMAs
56. Concerning : AS TO
59. Move like sludge : OOZE
60. China company based in Stoke-on-Trent : SPODE
61. Jordan's Queen __ : NOOR. The widow of King Hussein of Jordan. Wiki link.
62. Prohibitionists : DRYs as opposed to the WETs.
63. The "A" in YMCA: Abbr. : ASSOC. (Young Men's Christian Association)
64. Yankee who passed Willie Mays on the career HR list on 5/7/2015 : A-ROD
Down:
1. "__ & the Women": 2000 Gere film : DR. T
2. "Hollywood Squares" win : O-O-O
3. Convinces : PERSUADES
4. Basic nature : ESSENCE
5. Errand runner : LEGMAN. Using one's shanks' mare.
6. Ready to chat, nowadays : ONLINE
7. "__ you so!" : I TOLD
8. Unfavorable change of fortune : REVERSAL
9. Before, in verse : ERE
10. Hallelujah kin : HOSANNA
11. Improve : AMEND
12. Campus recruiting org. : ROTC. (Reserve Officers' Training Corps)
13. Medicinal measure : DOSE
21. Like a specially formed committee : AD HOC
22. Grooved on : DUG
23. Not as well-done : RARER
24. University of Maine town : ORONO
25. Seine tributary : OISE
29. Cut for an agt. : PCT. (%)
31. Jointly underwrite : CO-SPONSOR
32. Math relationship : RATIO
33. Skater Brian : ORSER. He is the 1984 and 1988 Olympic silver medalist, 1987 World champion and eight-time Canadian national champion. ~ Wikipedia
36. "As I see it," in textspeak : IMHO. (in my humble opinion)
37. Popular antique desks : ROLLTOPS. Out of my price range.
38. Trudges (through) : SLOGS
41. Tries to avoid a pothole : SWERVES
44. State whose name is part of its capital : INDIANA. (Indianapolis)
46. Actress Gardner : AVA
47. Operetta set in Japan, with "The" : MIKADO. (An archaic name for the Emperor of Japan.)
48. "Be right there!" : "ONE SEC!"
49. Swanky : RITZY
50. "Let's go, amigo!" : "¡VAMOS!"
51. Frame of mind : MOOD
52. __ about: approximately : ON OR
55. Pres. Mandela's land : RSA. (Republic of South Africa)
57. Also : TOO
58. Command from a maj. : ORD. (order) (ick!)
Argyle