Yup...post pics of the floor from above and in the cabinets and from below if you have them...be sure you are COMPLETELY supporting that floor if it is dismounted though! Common indicators of interior damage are not contained to, but include dark stains near the vents or in the front/rear panels where they meet the roof. Damage beneath the windows can also mean the Pirelli seals have been shot for long enough for water on the highway to be thrown up and sucked into the void between top/bottom. On the other hand, some damage to the wood may be attributed to condensation dripping down from the windows and their aluminum frames that soak the wood which is then actually rubbed by a decently working Pirelli seal also.
As you can read in many posts about Alaskans, the weight of them is of concern to those who have 1/2 ton and even some 3/4 ton trucks because while the difference in weight between a stripped down 8 ft. NCO and a fully loaded 10 ft. CO is quite a lot, one needs to consider how much "stuff" you intend on carrying in it as well.
As one might appreciate, not all 1/2 tonners (or 3/4 tonners) can SAFELY carry the same amount of weight on the rear axle!
My first Alaskan was an 8 ft. NCO mounted on a 1985 F-150 4x4 long bed. While I did not have a huge motor in it, it did handle that weight and didn't hardly sag when mounted, and it did fine on flat expanses of freeways....it wasn't gonna win any race to the summit of Emigrant Pass on I-80!