You have many options for Ponta Delgada. Unfortunately, you never know what the weather will be in Sao Miguel. You certainly can book a guided tour beforehand.
Here are some of my ideas.
A taxi stand is at Portas da Cidade, about a 10 minute walk from Portas do Mar. At the corner, as you pass the statue of Goncalo Velho Cabral there is a sign with the posted options and costs for a taxi tour. This is the price for the taxi (up to four passengers), not per individual. A big group using a minivan taxi will pay 25% more. Taxis only take euros. There is Multibanco (ATM) also at one of the corners on the main road near the statue.
My advice, if the weather is nice and sunny, is visit Sete Cidades. Ask to include Miradouro da Boca do Inferno(add a bit more to the price). It costs about 60 euros and will take around three hours. If you want to extend the taxi tour, visit Plantacao Ananas A Arruda. This will also increase the cost, but worth the money and time.
Then you can do part of my walking tour to include the following visits: Forte de Sao Bras, Igreja de Sao Jose, Santuario do Senhor Santo Cristo dos Milagres, Torre de Relogio, Igreja Matriz de Sao Sebastiao, O Rei dos Queijos (next door is Mercado da Graça), Museo Carlos Machado, Igreja do Colegio dos Jesuitas (next to the Bibloiteca Municipal at Largo do Colegio), and finally Jardim Botanico Antonio Borges. Lunch (12-3) can be at Trianon in the rear of the bakery. You can also just do this walking tour without going on a taxi tour.
Send me a Private Message with your email address and I can send you a photograph of the taxi tour options and I can also answer any specific questions you have.
