I do know... because it has happened like 10 times.
If NY gets a top 4 pick I think they'd give the pick and some other stuff for Don... if they don't I think they'd unload all their future picks and current prospects except RJ to get him (not that RJ is untouchable, but I'd think they would want to pair them together). A number of other teams would likely offer similar packages.
The biggest gains come from being able to get draft capital from Royce, Mike, and Bogey since you no longer have to try to be good or keep his friends around. In the Rudy trade you might still do the Atlanta deal but you flip Collins for draft picks and young players. You get to reset the timeline of the whole team. Having guys on multiple timelines is fine if you have young replacements coming up to replace the parts that age out. Joe aged out... Mike will soon... Bogey soon after.
You can also build without constraints... no small guards... get some elite wing talent... no limited centers... focus on getting as much two way talent as possible while you build.