Converting the Trumpeter 1/350 Lexington (with already-widened flight deck) into a later Sara would be similarly straightforward - now with decently accurate hull, so much less to do, there.
In both cases - Sara and Big-E - conversions would entail as much or more addition/replacement of weapons as anything else.
A Ranger CV-4, however, would be primarily structural mods - though a lot less than you might think, (especially) from the Revell Yorktown mold. If you take a good look at hull plans for Ranger vs the (as-built) Yorktowns, you will see how similar they really were - even the waterline lengths - such that you would get a 480-scale Ranger, when bashing from a 490-scale Yorktown.
That could look pretty spectacular alongside your Revell 480-scale CA (or CL) - equally well for an Operation Torch depiction, or pre-war-exercise mock operations against the Panama Canal. And I know somebody who has all the weapons and planes you would need - whether the F4Fs for Operation Torch, or the pre-war F3Fs, SBCs and TBDs - too!