My inclination would be to trade both.
On Tarasenko, it seems the bad blood (to extent that there really was any) has cooled, but I still don't expect him to necessarily be eager to stay after his deal is up. I expect Army has, and will continue to have, a read on whether he has any interest in staying longer-term at a price that fits with our cap structure. If not, I could see him in a deal that brings back a Top 4 LD, but that would necessarily have to include the ability of the other GM to negotiate the framework for an extension unless the player we're bringing back only has one year left as well. He's a PPG player again, and I would expect teams to be lining up for a chance to cut the line to nab him before he becomes a free agent if the price is right. Given the recent history, if there is any reluctance on his part to negotiate this offseason, Army should be asking for his list and taking the best deal he can find.
On ROR, I would expect he is going to be looking for a long-term deal (6-8 years) and I fear this would end up similar to the Backes situation. I don't feel like he will decline as quickly as Backes did, but as others have alluded to I feel like we've seen his best hockey already. If he's moving on at the end of next season, maybe we can move him somewhere that he is willing to extend and can get closer to market value back. Since he's signed one deal (offer sheet) with them already, I wonder if Calgary would be interested in him at his asking price to strengthen themselves up the middle in exchange for the RFA rights to Tkachuk if Tkachuk is unwilling to sign in Calgary long-term and instead is inclined to accept his QO and become a UFA in a year.