When we visited Yosemite National Park this past summer (June 2005), we stayed at the Oakhurst Lodge in Oakhurst. They provide free all-you-can-eat continental breakfast that includes muffins, toast, bagels, coffee, tea, hot chocolate and orange juice. They also have wifi in some of the rooms but it's best to request a room with wifi when making your reservations. Although it's not free, the prices were reasonable.
As we went on a train ride, we talked to other people visiting the area and they mentioned that they regret staying inside Yosemite National Park. At the place they were staying at, they didn't have a phone, television and had to worry about mosquitos. We didn't have a problem with any of that since the rooms at Oakhurst Lodge are equipped with a phone, a television set and even a mini refrigerator.
If you're planning to visit Yosemite, I would definitely recommend staying in Oakhurst and not Mariposa. The reason for that is because there are a lot more places to go in Oakhurst such as fast food restaurants, stores and only about 10-15 minutes drive away from a huge casino (Chukchansi Casino).