I recommend whole day trip from Madrid. With travel, a half day trip would not provide enough time to enjoy the cathedral and other sites. The tour guide was an excellent source of information. I didn't do the lunch package and had time to enjoy tapas in Toledo at a bar along the Calle San Tome. The restaurant at the end of the San Martin bridge where we were to meet the bus also had excellent tapas with local white wine.
It was a damp day for sightseeing, but our tour guide managed to make our trip to Avila and Segovia interesting. I wasn't impressed with the lunch package and would recommend taking the time to tour Segovia or enjoy tapas. The sun came out as we toured the Alcazar in Segovia. Our guide provide the opportunity for a little shopping and various sites from which to take photographs.