You are absolutely right Asturias56, there are multitude of issues with it, but it is something that was in their plans during the cold war too. Through Sweden to Norway. Another plan they had was to isolate Scandinavia by the sea, and that meant placing tremendous task force to the Norwegian sea, in which Murmansk was the key. But at that time the Warsaw treaty had a direct sealine all the way from Finnish border to West Germany and they had big portion of the Baltic sea in their hands. So in essence they couldn't do it nowadays with any significant benefit and stepping on NATO's toes.
Coming back to modern day, the russians have started to re-arm Kola peninsula very heavily during the past five years. Refurbishing old airbases and submarine bases and establishing new troops along the entire Finnish border gives a hint.The armament includes anything and everything from special forces to nuclear weapons.
The issue is that Russias internal propaganda relys heavily on external threats. If there isn't any, one is made.
https://www.csis.org/analysis/ice-cu...kola-peninsula
The problem is, the way I see it, that you really can't predict the irrationalism of the russians. Who in their right mind thought ten years ago that russians would take crimea at this age and time? And yet they did. And the russians are feeding the war in Ukraine too, but denying everything (MH17). From Nordic point of view: the heat comes from the east. If it doesn't, they have flanked.