Google maps is your friend here.
Once you know the location of the villa, you just get directions to a point of interest in the village and it tells you how far it is, if it's hilly etc.
Same for getting from the airport, it's a bit of a trek from the nearest airport, Girona, so I'd expect a taxi to be expensive, so if you don't want to pay £££s, I'd look at other options like public transport or shared transfers. Often the property owners can advise on the different transfer options.
I went to the area about 30 years ago and don't remember a huge amount about it. We drove there from northern England, which was the done thing at the time because this was before low cost airlines so this was a bit of an adventure. I'd love to go back but just haven't got round to it.
L'Escala looks like a good place for you. We stayed in a Eurocamp type place a bit further south. I remember we went to Empuries (Roman ruins) further up the coast, Roses a nice town and a water park. But we drove everywhere. You might be able to get to these places on public transport or excursions, so worth looking into while you're there - I've found it's sometimes difficult to find out about Spanish public transport options online unless you get the app for the local bus/train company so just easier to pick up leaflets at the bus station or tourist info place when you're there.
You can probably go on a boat trip to Islas Medes, which is a marine reserve so could be good for snorkelling.
Girona city itself is worth it for a day out. But as it's quite a way away, I'd probably combine it with the trip to or from the airport, even if it means booking another night's accommodation.