Workouts for Returning Swimmers?

My apologies if I am posting in the wrong place or I'm repeating a post. (I'm kind of new to the site as it exists today.) I am a 40-something female who is trying to return to swimming after a few years break. I swam in high school and college and returned to swimming (on a fantastic master's team - Go SV Gators!) in my late 30's. But, after a relocation and 2-3 years out of the pool, I am again extremely out of shape. I am trying to get back into swimming shape - but this time on my own, without the benefit of a master's team and coach to support me. I am looking for workout ideas that are not necessarily for NEW swimmers, but for RETURNING swimmers who have been out of the pool for a while and are out of shape (starting again). My tendency is to get in the pool and do distance, but I'm sure there are better ways - especially with an aging body - to go about this. Thanks for any ideas.