The Laugavagur ("path of hot springs") is Iceand's most famous trekking path. It leads from Landmannalaugar to Þórsmörk. You can travel it in both directions.
Its overall length is 54 km, itss highest point is 1.050 m
The potential starting and ending points Landmannalaugar, Þórsmörk and Skógar can be reached by bus easily during the summer months.
You have to bring your own food but you can use the cottages' kitchen. Camping is allowed only around the cottages. (source: wikipedia)