Island hopping – A letter from Gladys

Question

Letters from Gladys are geography-themed standalone crosswords. Each puzzle has five thematic answers, which are places, sights or landmarks in or around a certain location (in this case, an archipelago). Each thematic answer is notable enough to have its own article in the English Wikipedia, although not necessarily under the same name that is used here. The goal is to fill the grid, identify the thematic answers and guess the name of Gladys’s destination, which is not indicated in the grid.

Dear Puzzling,

This time I’m doing some island hopping in a place I have never been before. (Yes, those exist!) I have enjoyed a white sandy beach, seen some spectacular mountain scenery, explored the underwater world in a world-class dive spot and visited a historic site I am sure you have heard about. Can you guess where I am?

Wish you were here!
Love, Gladys.

Across
1. Computer bearing a picture of a partially eaten apple and a white parrot (5)
4. Manly yet childish, gutless (5)
7. Is Gladys extremely staunch Christian traditionalist? (5)
10. Idyllic – close to desert – surfing place at sea? (7,4)
11. Leading figures of USSR? Not those I look up to (5)
12. He wrote music for militants (3)
13. Engineer segregates hidden features (6,4)
14. Fantasy character with a hideous appearance – a real killer (4)
17. Perform music with lyrics about Michael meeting with Elizabeth, briefly shooting amorous glances (10)
18. Oscar visiting Indian city's marketplace (5)
19. Give up princess's kiss, interrupted by queen (8)
21. Princess hugs British couple from Emsworth, getting disease (8)
23. One side of a page of poetry, mostly old (5)
24. Koala in a UK resort town (6-4)
27. Rib steak starter aboard airplane (4)
28. Glimpses of the past of sponsors behind comic book superhero (10)
29. It's spelt differently (3)
31. Article: "Breaking news! Unknown person entrusted to take care of child" (5)
32. HR meddled with polar bear attack location (5,6)
33. Woman suspended by Explorer (5)
34. People like Peter Higgs captured very short-lived particle? (5)
35. Trails – do NC natives have tar on theirs? (5)

Down
1. Nets regularly supporting weak palm trees (6)
2. Chris Pratt has finally received old lady's instant packages (9,8)
3. Spectacular landform misrepresented in a cinema? No way! (6,6)
4. Petrochemical energy reduced by 50% following lead of automobile innovator (7)
5. Children's hero from the Rainbow Kingdom leading Greek-Italian film (4,4)
6. Selecting only the upper halves up top makes good quality (2-2)
7. Something one might drink inside of bar? More than half of two pints (4)
8. Mountain climber struggling, gripping side of cliff with energy, is capable of getting across in two directions (17)
9. Beginnings of heavy ash discharge, in accordance with a volcano (9)
15. Biblical king with large, hollow eyeball (4)
16. "What's the reason to give up ecstasy?" said German composer, having introduced aforementioned drug to coastal area (7,5)
19. Say, Niels Bohr's got very peculiar joy: He takes in expired salts (4,5)
20. Australian cooler's inmate has thick, ugly feet (4)
22. They drive in some of the fastest competitions on Earth and Venus (8)
25. Raise shelter for ICBMs perhaps north of N.Υ. (7)
26. When included in operating system, a virtual assistant is a wielder of enormous power (6)
29. Class taken by twenty people (4)
30. Can food plans turn up? (4)

Answer 1

I can't believe that Gladys had never made it to

Hawaii!

The completed grid:

Across clues:

1. Computer bearing a picture of a partially eaten apple and a white parrot (5) - MAC + A + W
4. Manly yet childish, gutless (5) - BUT + C_H
7. Is Gladys extremely staunch Christian traditionalist? (5) - AM + I + S_H
10. Idyllic – close to desert – surfing place at sea? (7,4) - PERSIANGULF(-c)* &lit
11. Leading figures of USSR? Not those I look up to (5) - U_ N_ T_ I L_
12. He wrote music for militants (3) - IRA ddef
13. Engineer segregates hidden features (6,4) - EASTEREGGS*
14. Fantasy character with a hideous appearance – a real killer (4) - ORC + A
17. Perform music with lyrics about Michael meeting with Elizabeth, briefly shooting amorous glances (10) - S(MICK + ER)ING
18. Oscar visiting Indian city's marketplace (5) - AG(O)RA
19. Give up princess's kiss, interrupted by queen (8) - DI'S(ANNE)X
21. Princess hugs British couple from Emsworth, getting disease (8) - LE(UK + EM_)IA
23. One side of a page of poetry, mostly old (5) - VERS(-e) + O
24. Koala in a UK resort town (6-4) - KAILUAKONA*
27. Rib steak starter aboard airplane (4) - JE(S)T
28. Glimpses of the past of sponsors behind comic book superhero (10) - FLASH + BACKS
29. It's spelt differently (3) - TIS* &lit
31. Article: "Breaking news! Unknown person entrusted to take care of child" (5) - N(AN)N + Y
32. HR meddled with polar bear attack location (5,6) - PEARLHARBOR*
33. Woman suspended by Explorer (5) - SUS + IE
34. People like Peter Higgs captured very short-lived particle? (5) - ME(SO)N
35. Trails – do NC natives have tar on theirs? (5) - HEELS ddef

Down clues:

1. Nets regularly supporting weak palm trees (6) - MAPL* + _E_S
2. Chris Pratt has finally received old lady's instant packages (9,8) - CHRIS + _T(MA'S PRESENT)_S
3. Spectacular landform misrepresented in a cinema? No way! (6,6) - WAIMEACANYON*
4. Petrochemical energy reduced by 50% following lead of automobile innovator (7) - BENZ + ENE(-rgy)
5. Children's hero from the Rainbow Kingdom leading Greek-Italian film (4,4) - TRUE + GR + IT
6. Selecting only the upper halves up top makes good quality (2-2) - HI(-gh)FI(-ve)
7. Something one might drink inside of bar? More than half of two pints (4) - _A_ + QUA(-rt)
8. Mountain climber struggling, gripping side of cliff with energy, is capable of getting across in two directions (17) - INTERCOMMUNICABLE*
9. Beginnings of heavy ash discharge, in accordance with a volcano (9) - H_ A_ + LEAK + A LA
15. Biblical king with large, hollow eyeball (4) - OG + L_E
16. "What's the reason to give up ecstasy?" said German composer, having introduced aforementioned drug to coastal area (7,5) - WAIKIKI~(why kick E?) + B(E)ACH
19. Say, Niels Bohr's got very peculiar joy: He takes in expired salts (4,5) - DA(V + YJO*)NES
20. Australian cooler's inmate has thick, ugly feet (4) - _E _S _K _Y
22. They drive in some of the fastest competitions on Earth and Venus (8) - WILLIAMS ddef
25. Raise shelter for ICBMs perhaps north of N.Υ. (7) - UP + SILO + N
26. When included in operating system, a virtual assistant is a wielder of enormous power (6) - O(SIRI)S
29. Class taken by twenty people (4) _TY PE_
30. Can food plans turn up? (4) - SPAM<