Edited Jul. 12, 2016 at 12:10 p.m.
Every line has a young player on it, with two veterans to cover for them (and their mistkes), and allow us to roll 3 consistent lines that should be able to produce offensively, and be solid in their own end. Lineup, has a lot of versatility in it. Backes starts games as your #3 center (but still gets solid minutes with EV, PP, and PK) and is easily slid up and down the lineup (C --> RW) if needed. With Austin Czarnik winning a spot as the 4th line RW, he is able to get his feet wet a bit, and is a threat to easily slide up into a #3 center spot when Backes is moved up. Riley Nash is also an option to do that (solid numbers playing with a offensively lacking Carolina team).
Defensively, it's not going to be perfect. Hell, the chances of the Bruins even getting a top 4 defenseman (Trouba, Ceci, Shattenkirk, Dumba, Brodin, etc.) is getting slimmer by the day. But for the purpose of the mock, the Bruins acquire a young promising defenseman from Ottawa in Cody Ceci. Ceci has shown solid all around potential, while starting off a lot in the defensive zone. He is very Boychuk-esque. Solid skater, moves the puck well, can play physical, and has a nice shot. Right handed, and would be a solid partner for either, Chara or Krug. With that said, have to spread out the defense a bit. A Chara-Ceci pairing would be too top heavy, imo. Krug can't cover for Colin Miller also (and I don't want Kevan Miller in the top 4). Now, with this mock (as well as some other's I've done) the Bruins have plenty of in-house options in case injuries, or failures happen. If Colin doesn't work out, or Kevan gets hurt, Brandon Carlo should be the #1 call up for the right side. Many ways you can go with that..... Ceci up to #2, Carlo to #4 (or #6 -- Kevan sliding up) or Carlo straight to #6 if Kevan gets hurt...Did i lose you yet? lol....
On the left side, the Bruins prime candidates are Matt Grzelcyk, Linus Arnesson, and (my personal favorite) Robert O'Gara. JML can also play both sides, so if needed, you could leave Carlo in the minors, slide him up (or over) and call up/play one of the two mentioned.