Last year, the 36-year-old stunned the motor racing world by skipping Monaco to do the Indy 500, and right now he is testing in preparation for the forthcoming Daytona 24-hour.
Alonso makes no secret of his desire to win the rare 'triple crown' by adding Indy and Le Mans victories to his Monaco GP trophy, but he also says F1 is his number one.
"Of course I focus first and foremost on Formula 1 and the goal of winning a third world title," he is quoted as saying in Daytona by Speed Week.
"With the Renault power unit we should be able to get involved at the front again.
"However, I also have plans for classic events that do not overlap with the F1 calendar. This race (Daytona) is the first step in endurance racing and of course I hope I like it because Le Mans is another goal of mine.
"If Le Mans works out this year, it would be great and hopefully next year I could be back at the Indy 500."
However, he says he does not have his sights set on Nascar.
"Those cars require a unique driving style which can only be acquired through a lot of practice and I do not have that many free weekends," he said.
"But after the 24 hour here I'm sure I'll watch the Nascar race, but that will be my only step towards Nascar - watching on TV."
Alonso won his last two titles in 2005 and 2006.