Based purely on the live numbers on Cap Friendly right now, I count:
$196.545M in cap space from teams below the cap... Then $23.720M it teams that are over the cap. So if you get every team above, below the $82.5M you'd be looking at ~$172.8M in space right now. That said, obviously LTIR players will have an impact on that and no doubt Cap friendly doesn't have every roster perfectly setup at the moment either, some prospects will make the NHL, some veterans could end up buried, etc. etc. For example Colorado's roster on cap friendly has Ben Meyers in the AHL but he'll clearly be an NHL guy this year, on the flip side they have Andreas Englund on our NHL roster, he's 99% to be an AHL guy to start the year. Lots of changes from every team between now and then.
There's also by my count, assuming every team goes with a full 23 man roster... 74 open spots remaining.
There's still quite a few UFAs left to sign as well that will eat a decent chunk of that $172M in cap space. Kadri and Klingberg alone could very well end up taking 10% of that space. Plus there's still some guys like Rodriguez, Bergeron, Heinen, Kessel...
And then there's a bunch of RFAs as well. Tkachuk and Bratt will certainly eat 10% of that $172M combined. Then you've still got the likes of Mangiapane, Robertson, Crouse, Zacha, Puljujarvi, etc. etc. Long story short is there's very little cap space in general available right now. I think the remaining RFAs alone probably eat up ~$125M if not more of that space.
And the thing is, not all teams are going to be salary cap teams either. Arizona will almost certainly be a cap floor team, a number of other teams haven't shown any interest in being near the cap for a number of years either now. Buffalo is $19.6M below the cap with a 22 man roster, they aren't spending all that money or even close at this stage. Anaheim is still $8.5M below the Floor even... Now they do have 6 roster spots to fill(And I'd be willing to be at this point they're probably one of the only teams remaining that are willing to take on a major cap dump, but they're probably asking for a very high price to take that dump), but they certainly wont spend to the cap either.
So, for the teams that are trying to move cap right now, its incredibly difficult to do so it would appear... Judging by the Bjorkstrand trade today, its going to be ridiculously expensive to outright dump a bad contract. Bjorkstrand is a legitimately good player and CBJ basically had to give him away for free.
Teams like Toronto, Vegas, and even Colorado right now if they want to sign Kadri, or the Islanders if they want Kadri... Those teams are gonna have to pay a lot to move cap, or dump a really good player for literally pennies on the dollar.