Roslagsleden is a hiking trail in old viking areas. It was started 1977 and have been extended to Grisslehamn. You can get to the starting points by commuting traffic. It starts near Danderyds kyrka and ends in Grisslehamn. It is 190km long and is well marked with good camp grounds, water sources and cafées and lodging. There is 11 sections, if you are fast/running you can cover more sections.
Google map for Roslagsleden with water sources, wind breaks and cafés and lodging.