Have a look at the amazing Sörmlandsleden trail:
http://www.sormlandsleden.se/Default.aspx?langID=1033
(It is a 950 km loop of trails that goes around Södermanland,
one of the finest parts in Sweden. It is connected to other
trails in Europe, so you can walk all the way to Rome if you
want to.)
It has lots of suitable loops, or even better; access points
to busses and trains.
It is an easy trail to walk and it is always fairly close to the
"civilization", witch makes is safe to walk. There are also some
parts of it that really have a genuine wild outdoor feeling about
them.
There are some cabins to rent along the trail, but they might be
heavily booked during the summer.
A better alternative would to book cabins at normal camping sites
or at other cheap accomodation. Or you can sleep in the shelters
that are provided along the trail.
I love this trail and I've been at it for more then 20 years without getting
bored with it. There are cliffs, caves, lakes to swim in and even a stream
of ground water that just comes out of the ground at one place, with absolute
fresh water you can drink.
You might see moose, wild bores, eagles, foot prints from Lynx and
a lot of other animals.
And you can plan it and choose just what you want to experience,
how hard the walking will be and what level of comfort you will have.
It's a long time until you come here, if you do, but I might be able
to assist you in any way you want...