Mojacar and immediate area , apart from the Pueblo, is not typically Spanish anymore. IMOP it is just quieter form of Benidorm and overloaded with Brits.
Suggest you look 35 mins further north and the very Spanish coastal town of Águilas for the start of your journey.
Many delightful small coastal villages between Mojacar and Aguilas worthy of a visit but because out of season wouldn’t recommend staying because they are few permanent residents in situ.
The Spanish city of Lorca with its lovely castle is 20 miles inland via excellent roads plus in Aguilas one can get a most enjoyable, and inexpensive, train journey ( about 1 1/2 hours ) to the facinating city of Murcia.
Cartegena is also a fabulous must visit Spanish City with its amphitheater and ancient buildings. This is only 40 mins further North easily accessible via toll road.
Personally would consider Valencia instead of Denia....the latter an area where Brits are also catered for. As is Mazarron Alicante and Benidorm.
If you do your research am sure you discover the Spain you seek.
Happy travels