The cap will likely rise these next 2 years since it's risen every single year since the lockout. My guess is that it will be close to $70 million by the time the 13/14 season starts which is the year the cap calculations will really matter to the Oilers.
Here's my rough template for what the roster would have to fit into to be at that cap:
Forwards:
7-6-5
5-4-3
2.5-2-1.5
1.5-1.25-1.25
.8-.8
Forwards total 41.6 million
Dmen:
6-5
3-2.5
1.5-1.5
.8
Dmen total 20.3 million
Goalies
5
2.5
Goalies total 7.5 million
Grand Total 69.4 million
I think those are pretty big numbers up above which allow for some big salary increases... and of course you shift and chop to arrange your pieces but I think with proper management this team won't get into cap trouble. I'm not saying it's impossible they do, but with awareness of the cap the team should be able to make the moves it needs to stay under the cap.
Worst case scenario we win the Cup and then stay a strong contender after ripping out depth pieces like Chicago.
None of us know what the next CBA will look like... and that likely goes for the NHLPA and all the owners at this point as well. There could be radical changes with buyout/luxury tax provisions or it could be more of the status quo... no one knows at this point. That's the wild card over the next 3 years and everything is just speculation and almost pointless speculation until we do know the realities of the next CBA agreement.