Michael plans do exist detailed deck plans however are fairly rare and original copies might be expensive and or hard to find. As for copies others on the message board might be of more help than I can be.
I have a THS copy of the deck plans of the Adriatic. Unfortunately the plans even using a magnifying glass in order to view them are still impossibly difficult. I am guessing because of the number of lifeboats that the plans are post-Titanic and with the designation Tourist Class [in place of 2nd Class] perhaps date from the 1920's.
What I am trying to understand is how 3rd Class passengers in rooms located in the bow section were able [if in fact they could?] to reach the main 3rd Class area in the stern.
From each of the two sections of "3rd Class portable berths" [82 and 182] on the Lower Deck there are stairs that lead up to the Middle Deck 'E'. The forward fight of stairs comes up to what is called the "3rd Class Passage". This leads to the "3rd Class Dining Saloon (Portable) 142 seats". The after of the two stairways comes out just forward of the Dining Saloon. There are also flights of stairs going up to 3rd Class Entrances on Upper Deck 'D', but no way that I can see aft from any of these areas to the main 3rd Class section at the stern, which include Port and Starboard Dining Saloons, a Lounge, a Smoking Room and a Children's Room, with berths on the Middle and Lower decks some of which are marked as being portable with others being Interchangeable with Tourist Class.
It may well be that there were in fact two quite separate 3rd Class areas, but it would be appreciated if this someone could confirm this; or if there was an access passageway between the two areas, advise where it was located. Any help appreciated.