Reykjavik is a walkable city, and most of the points of interest in this itinerary are within walking distance of each other. However, you may want to consider renting a car for the day trips to the Reykjanes Peninsula and the Golden Circle. Renting a car can cost around $60-$100 a day, and many car rental companies provide free pickup and drop-off at your hotel. There are also plenty of public transportation options, including buses, taxis, and ridesharing services like Uber and Lyft.
If you have more time, consider taking a whale watching tour or visiting the Blue Lagoon. If you have less time, you can shorten the day trips to the Reykjanes Peninsula and Golden Circle by skipping some of the stops. Don't forget to dress in layers and wear comfortable shoes, as the weather in Iceland can be unpredictable and you'll likely be doing a lot of walking!
Reykjavik has two airports: Keflavik International Airport (KEF) and Reykjavik Airport (RKV). Keflavik International Airport is the main international airport and is located 50 kilometers southwest of Reykjavik. It takes about 45 minutes to get to downtown Reykjavik by car or bus. Reykjavik Airport is located in the center of the city and primarily services domestic flights, as well as flights to Greenland and the Faroe Islands.