Good Morning Dave,
I’ve been out that way running, but don’t “know”the area.
Found a feature in Dorset Life magazine
https://www.dorsetlife.co.uk/2015/04/lakes-lagoons-and-ponds/
It's Dorchester way, off the top of my head i'd recommend a visit to the Tank Museum at Bovington, the abandoned village of Tyneham ( check for access due to being on MOD land for the firing ranges ) The Square and Compass pub at Worth Matravers, and Monkey World. Weymouth is very Victorian. There's a steam railway between Swanage and Corfe Castle which is well worth it, I like Swanage, some proper fish and chip shops. Beaches tend to get rammed in the grockly places like Poole and Bournemouth but Swanage and Weymouth beaches are quieter. There's a fabulous beach at Shell Bay Studland, the middle mile or so is a Naturist beach. Dorchester pubs, "Proper Pubs "the "Blue Raddle" ( does home made food with a good veggie selection) and the very small and hidden away Convivial Rabbit. There's "Copper Street Brewery" opposite the railway station at Dorchester South, a nice micro brewery with some good beers, but again very small.