Thanks everyone.
I took the liberty of contacting the Fleetwood folks directly and they sent me a pdf of the original 1990 brochure. What a time warp! I have the actual numbers now in case anyone else out there needs them. Here they are:
Tank holding capacities (in gallons): Freshwater: 40; Water heater: 6; Waste water holding: 30; Gray water holding: 30; Appliance LP: 14
Cheers.