After the lookout, the walk isn't as scenic. The path continues through the dunes, but deeper within them. Also, the path does leave the dunes and you will walk along Oceanside Promenade and a large carpark before reaching Tom Simpson Park at Mullaloo Beach. It is still a pleasant enough walk, just nothing to write home about.
Another option after the Mullaloo Beach Lookout is to leave the main path via the sandy track at the next carpark and walk south along Mullaloo beach itself (alternatively, you could always call it a day and catch a bus on Oceanside Promenade or even walk back to Burns Beach!). Either way, you will find yourself at Mullaloo Surf Life Saving Club and Tom Simpson Park (picnic and toilet facilities available).