Though Iceland Walking Explorer is rated "Moderate" by Exodus, I found the walking (and this was not walking - this was full on trekking!) to be much more than what I would considerate to be moderate, and in looking back on the itinerary feel that it slightly underemphasizes the difficulty of the trip. There were times we were lumbering up mountains with steep vertical ascents, without any trails to follow. BE PHYSICALLY PREPARED FOR SOME VERY TOUGH DAYS OF TREKKING, oftentimes between 6-8 hours per day. Bring WATERPROOF hiking boots and trekking poles (or walking sticks) are highly encouraged! Bring a headnet for the midges at the Lake, because those bugs are RELENTLESS!!
With that said, the physical challenge of some of those days was ABSOLUTELY AWESOME and I would do it again without question.
The weather in Iceland can change dramatically - bring plenty of layers, waterproof trousers and jacket, gloves, fuzzy hat, sunglasses, etc. A warm sleeping bag is a must, even in the summer! Bring earplugs - you will be sharing a tent with someone for 10 days!
Iceland is an amazing country, which cannot be compared to any other, nor can it be described appropriately...you simply must go there to see and experience it for yourself. When I left Iceland after 15 days I felt a bit like I was leaving a part of me behind, and it is the one country that, when asked of me "Would you go back to any of the places you've visited?" I would choose.
It is a once in a lifetime, must-see locale, and I highly encourage anyone considering a trip to Iceland to consider Exodus's trip. I spent months looking for the "perfect" Iceland trip but everything I found was either too short in length or a sit-on-a-bus-and-stare-out-the-window trip. Iceland needs to be seen as it should be: wandering the landscape, enveloping yourself in its wilderness. Spending 10 days camping, and spending two weeks driving and hiking in four different, unique locations in Iceland, is the ONLY way to see this beautiful country and be able to return feeling confident that "I saw Iceland."