You've picked quite an extensive area with some 200km from north to south. Bear in mind the closer you get to the beach area the more expensive the property. Slightly inland and they go down substantially. Trouble is the public transport gets worse.
We picked about 8km inland and a town with an all round vibe and everything open. Just a 10 minute drive to the beach if we want it but we are in a quiet area which suits us fine although we have lots of bars and restaurants within walking distance along with half a dozen of the major supermarkets within a couple of k of us. Quiet when we want and busy when we want which suits us fine. And a 40 minute trip to the airport suits us as does the main motorway just 5 minutes away so we can go where we want with no hassle.
We travel up and down the coast spending a week or so in each place during the season. Altea is nice but a stony beach. Calpe and Villa Joyosa two of our favourites and we have Valencia for the times we want a city break. Then even further south to Almunecar, Cartagena or Mojacar, all an hour or two away. Train travel is cheap here and we can get to Barcelona from Alicante in 5 hours for about 60 euro and, sometimes, Madrid in less than 3 hours for the ridiculous price of 12 euro.
Guardamar del Segura has a wonderful beach but just going a few km inland to El Raso (still under Guardamar) and you get a lot more property and grounds for your money. But public transport like feathers on a fish.
A garden was essential so we could sit outside and tend the plants and we like eating outdoors as well so a gazebo gives us shade. Not too big a garden at our age but just big enough for lots of pots and bushes.
Evening meals under the stars enjoying a glass or two of something is one of the things we love here along with breakfast in our back garden among the hibiscus and bougainvillea.