The following are each good day trips from Reykjavík. If you have time, these places are definitely worth 1-2 nights away.
Búðir – 2 hours from Reykjavik – easy drive
Stay: Hotel Búðir
A very special hotel and place. Amazing food. Views of Snaefellsjokull glacier (where Journey to the Center of the Earth book and movie are set) and the ocean/beaches. Set among an old lava flow there are beautiful walking and running trails. Gorgeous black church there too with mountain and glacier views.
The peninsula the hotel is set on is considered by many to be “Iceland in miniature.”
To do: check out Djúpalón Beach
black church
walk some trails by the coast with glacier and sea views
eat delicious food
Eat: Hotel Búðir
On way to/from Búðir- stopin Borgarnes at the first bakery (“Bakari”) on the left connected to the grocery store “Hagkaup.” Amazing sandwiches, sweets for the road or to eat there with a nice view of water and mountains and great soup of the day. Great food for the $$ here.
South Coast – 2-6 hours from Reykjavik – long drive if you go all the way to Jokulsarlon. Not too far to go to/from Reykjavik in one trip if you just go to Skogafoss.
To do: (in order of approach from Reykjavik)
Seljalandsfoss (tall waterfall)
Skogafoss (tall, wide waterfall – almost always a rainbow if any sun is shining), Jokulsarlon glacial lagoon (amazing blue water with chunks of icebergs floating off to sea – also check out the black sand beach closer to the coast – beautiful icebergs sitting on black sand and you can walk among them).
Could also do a glacier adventure here as the road to Jokulsarlon (Route 1 – the only road around the island) drives right south of the largest glacier in Europe (Vatnajokull).
Eat: Gamla Fjosid – an old cow farm house near the road on the right from Reykjavik. Very good food. It lies between Seljalandsfoss and Skogafoss.
Stay: any cute place near where you want to stop – or just drive back to Reykjavik
“Golden Circle” – about 2 hours from Reykjavik
Disclaimer: this will be the MOST CROWDED option but still not crowded compared to an east coast beach in the US in summer.
To do: Laugarvatn Fontana – swim/chill in hot water here- next best to Blue Lagoon but doesn’t have the milky white water.
Geysir – erupting geyser
Gullfoss – large waterfall
Eat: Fridheimar – Tomato greenhouse You have to like tomatoes and you HAVE TO MAKE RESERVATIONS if you wish to eat. But it’s a special place.
Stay: Ion Adventure Hotel – Haven’t stayed here but it’s beautiful! And close to the Golden Circle.