Now that I think about it, if I were Boston I would:
Draft Fultz
Trade Brown, Smart, Rozier, and Jackson to a young team for 1 or 2 future 1sts
Trade Crowder, 36, and 53 to Portland for their 2018 and 2020 1sts.
Use the resulting cap space to sign Hayward and Griffin/Ibaka
Use the MLE and minimum contracts to sign guys like Sefelosha, David West, and Tiago Splitter
Thomas / Fultz
Bradley / Fultz
Hayward / Sefelosha
B.G. or Ibaka / West
Horford / Splitter.
Future 1sts other than their own: 2018 BKN, 2018 POR, 2019 LAC, 2019 MEM, and the 1st they got for Brown and Smart.
In 2018, they could land a guy like Ayton, and use the future 1sts to fill out their bench. That starting lineup would contend, and Fultz, Ayton, and other young players drafted with those picks would be the future.
This is the best way to build a team IMO. Acquire/sign players, then trade those players for picks and get cap space, then use cap space to replace said players with equivalent or better FA players.
In the end, you add free picks, and stay just as good if not get better.
I'm gonna call it the Addition Through Recyclization process, or ATR. I'm gonna make this a thing.
I'll explain it through another example:
Say (hypothetically) Portland is at the cap line and trying to contend.
They have an older a SF who is willing to sign with them for $9M that's better than Harkless.
A young team is willing to trade a future 1st for Harkless because he's a solid young player on a decent contract.
So Portland trades Harkless for a future 1st, then replaces Harkless with a better player via free agency.
So Portland adds picks by recycling Harkless for a better player.
Addition Through Recyclization - ATR.