I don't know this route, Jim, but based on the article it's not along the ocean for a lot of the way. Estoril to the big beach at Guincho is a few kms, from there it goes inward to Sintra, then up to Mafra, Obidos and Alcobaca. Those places are all tourist destinations so there will be accommodation (not sure about Mafra, but the rest for sure).
What I would wonder about is whether its all on roads, though. If so, I don't think there's any advantage over the Caminho. If you do decide to stick to caminho through Alverca and Alhandra, Azambuja, etc, you can easily make use of the train line to jump up or back. That could help you if you're in a pinch with the heat. The commuter line runs as far as Azambuja. There is no shade at all between Lisbon and Azambuja, so it will be a killer if the temps are as high as predicted. I hope you work this out. Bom caminho, Laurie