DH and I went to Iceland in 2015 and loved it so much we were planning to go again in 2015 till he got sick. Even though I leave for Central America next month, I decided I HAD to go back to Iceland again this year so I'm going in August. I don't even look at air/hotel packages; I have an Airbnb apartment booked. A few thoughts:
1. Yes, food is expensive. I like the idea of protein bars; DH and I also got food from local grocery stores- sandwiches, etc. DH favored ramen noodles. I had to laugh that we were on an exotic, relatively expensive trip and that was what he ate!
2. I LOVED the "Inside the volcano" expedition (insidethevolcano.com). It's the only known hollowed-out volcano and the variety of rocks inside is pretty amazing.
3. If you drive or take a private guide and have chess fans in your party, Bobby Fischer is buried in Selfoss, not too far from Reykjavik.
4. Icelandic yarn is wonderful- there are a couple of shops in town that sell it in a huge variety of colors- natural but also dyed.
5. Check out the indoor public pools, which are geothermally-heated. I used one near the Hallgrimskirkja- Olympic-sized, not many people, $3/trip. Showering beforehand sans swimsuit in a large shower room (but separate for male/female) obligatory. Well, when in Rome....
I'm planning on day trips to Surtsey (a recently-formed volcanic island, which you can't actually enter, just sail close) and possibly Snaefellsnes, a peninsula further north. I looked at pictures on the web sites yesterday and got tears in my eyes. I am so glad to be going back soon.