If the current GS team remains intact, I don't think it matters which team LeBron migrates to. There's no team in the east, with exception possibly of Boston or Philly, where his presence could put those teams equal to the challenge.
And let's face it... the Lakers are a young team and are still 3-4 years away from being contenders in the West. Houston is another consideration, but how would Harden and Chris Paul adapt to LeBron running the show there? San Antonio? Although LeBron has spoken highly of Popovich - they're an older team and will most likely be without Kawhi Leonard next season.
LeBron moving to a western conference team is highly unlikely imo. At the very least, with only a few years left in his career, it would seem he would want to relocate to a team on the east coast that could potentially get him to the finals, where his chances are much higher getting to the finals versus having to go against the Warriors to get to the finals.
That leaves Philly, with Imbiid and Simmons as the significant contributors he could work with, who are both incredibly talented. They could, in some means, lessen his workload. It just seems the obvious choice, but then again perhaps Philly doesn't feel the need to bring him into the fold. Boston, I think, would fair the best. Great head coach, Kyrie's return next year would definitely be a huge bonus, as he's obviously played with James and knows his game. Boston has a great team, lots of role players who filled in and proved their worthiness.
If I were LeBron - I would be looking at Boston. Although Philly looks promising, I think they're still under-coached and lacking another player off the bench who could help get them over the hump.
Given that LeBron has another 2-3 years at-best to make a run, I don't think Philly ticks those boxes.
It'll be interesting to see where he goes, if he decides to leave, that is.
But if he's chasing titles - Cleveland isn't gonna deliver. Dan Gilbert has spent a lot of money to surround LeBron with the players he's wanted over the years, paid a premium with luxury tax fees to facilitate. He needs to surround himself with immediate talent, and both Philly and Boston meet that requirement imo.
I don't see him staying in Cleveland for that reason.