Lake Champlain was a long hulled Essex, the Trumpeter kit is an early war short hull. By the time your father-in-law was aboard she had undergone her SBC-27A refit, which made her look nothing like the Trumpeter Essex. Here's the breakdown of the SBC-27A refit:
Removal of the side belt armor and replacing it with a hull blister which increased the beam at the waterline to 101 feet.
Removal of the island twin 5-inch turrets and relocation of the new open 5-inch mounts to the starboard side along the edge of the flight deck.
Modifications to the Island which replaced the tripod mast with a single pole mast and redesigned smokestack.
Installation of larger and more powerful elevators.
Replacement of the H-4-1 Hydraulic catapults with H-8 Hydraulic catapults capable of launching aircraft up to 40,000 pounds gross weight.
More powerful bomb and ammunition elevators.
Equipment for the handling of Jet aircraft, including jet blast deflectors behind the catapults.
Increased aviation fuel capacity.
Installation of higher capacity aircraft cranes.
Three ready rooms relocated below the hanger deck.
Installation of an escalator along the starboard side of the island for aircrew to reach the flight deck.
Division of the hanger deck space by two fireproof steel doors.
Obviously, much of this doesn't matter if you're building a model, but it's going to be alot of work to modify the Trumpeter kit... sorry...
You best bet would be trying to find the 1/700 Jim Shirly USS Oriskany, which is in a modern configuration.
Regards,
Jeff Herne
Modelwarships.com