3D2N Jeju Island Itinerary Help

Hi Guys. I'm bound for Korea this 25th march and would be going to Jeju first before going back to Seoul. Would be great if I can get some advise on my Itinerary as its my first time there.

Day 1 - Reach Jeju at 2pm
Pick up Car Rental
Check in Hotel
Manjanggul Cave
Seongsan Ilchulbong Peak

Day 2
Jungmun Beach
Cheonjeyeon Falls
Teddy Bear Museum
Jeju Marine Park

Day 3
Mt. Hallasan
Gaetkkak JusangJeollidae
Loveland

Return flight to Seoul is at 9.25pm.

Hope bros out there can advise,
1. The flow of the trip
2. Meals recommendations
3. Any other must-go places I could add in

Appreciate all the help I could get. Thanks in advance.