I’m not “local” so comments are from experience with family there and more general tips from elsewhere in the country.
Riding? happymtb is your friend for detailed and useful local knowledge. The forum is good and you won’t have any problem asking questions in English if you don’t speak Swedish yet. Never had any access issues (as mentioned above??) elsewhere in Sweden which you’d expect with the Allemansrätten – basically responsible access is OK pretty much anywhere. CX seems pretty big in the Stockholm area if you’re into that. Riding (like much – but not all – of SE) is overwhelmingly flat though.
What are the people like? Well there’s about 2 million or so in the Greater Stockholm area, so you should be able to find someone you can get on with.
If you want more info on life in Sweden / immigration then there are a few of us on stw who have done things either SE-UK or UK-SE who might be able to help you.