I used YEHA bus tours for the only tour we did. English-speaking guides available (ours was young and willing to interact). Different tours for different sections of the island (I don't think there's a single tour for highlights of the entire island because it's pretty huge and transport takes quite a bit of time). YEHA picks up at most major hotels, I think. For drop-offs, they drop off at a number of major areas (perhaps 4?) instead of hotels. Tours aren't necessarily cheap, but they are perhaps the best way to see quite a bit in a full day (our tour was about 9 hrs.). I used Klook for discount tickets to the aquarium (a must!) and took a local bus from the main station. The info point at the station has English-speaking staff to help you make sure you get on the right bus. But the bus travel is slow and generally has quite a few stops. Great way to see that gorgeous island, though.

We stayed at the Shilla Stay Hotel a few months ago, which is probably nearby. I can’t recall actual taxi fare into town, but I doub it was north of US$15 max. Cheers! Sean