Well when it comes to anything Marvel at WDW, GotG is really the only plausible IP due to the killer contract Uni made with Marvel.
If a GotG overlay was to happen, while as lazy as it would overall be, a overlay of RnRC would make the most sense. Get launched into space, play the Awesome Mix on the on board audio, it can easily fit.
Now this rumor of overlaying ToT...yet keeping the hotel theme from the 1930's. That's a new one in terms of insane things said on a Disney forum.
If (and that's a mighty big IF) this actually happens, this would easily take the cake as the dumbest overlay idea because it just doesn't make any lick of sense. (As much as SGE is one of the worst overlays, at least I could see the direction they were trying to go in.) However, there would be a teeny, tiny part of me that would be looking forward to it since it could be a spectacular trainwreck. It would hurt like hell because of what it's replacing, but I wouldn't be able to take my eyes off it.
But seriously, if you're gonna' do a overlay, the best ride to overlay for this IP is RnRC.