Preamble:
If you are like me, you own a copy of Day of the Tentacle (DotT) Remastered but want to play the original version on you DOS computer, then this is the guide for you. As you may know, it is possible to extract the original game files from DotT Remastered and play it through SummVM. The steps for doing that are identical except we need to do more in order to get it to play in DOS. This is because ScummVM allows you to load the game as a folder bypassing the need for an executable and driver files. Fortunately we can get the needed executable and driver files through the DotT Demo.

Requirements:
Modern Computer (win2k and latter)
DotT Remastered (Steam or GOG)
DoubleFine Explorer
DotT Demo
DosBox
Dos/w9x pc

Procedure:
Note: Skip steps 1-5 if you have already extracted the game files for use with ScummVM.

Step 1:
Open DoubleFine Explorer and open the DotT Remastered files.

Step 2:
Save All Files to some empty folder.

Step 3:
Navigate to the folder that you just saved the game files to.

Step 4:
In that folder navigate to the classic folder. Then navigate to the en folder.

Step 5:
Make a new folder called DOTT and place all 3 files from en (monster.sou, tentacle.000, and tentacle.001) into it.

Note: If you wanted to use ScummVM, Just add a game by folder and it should work. But here is were things change when getting it to work in DOS.

Step 6:
Download the DotT Demo

Step 7:
Using DosBox, install the demo to some empty folder.

Step 8:
Using Windows, navigate to that folder. Now your will see a bunch of driver files (*.IMS files) and a DOTTDEMO.EXE file along with other non useful files .

Step 9:
Copy the driver files and DOTTDEMO.EXE to the DOTT folder created earlier.

Step 10:
Rename DOTTDEMO.EXE to DOTT.EXE
Rename tentacle.000 to DOTT.000
Rename tentacle.001 to DOTT.001

Thats it! You now have DotT for dos! You may be wondering about the lack of a setup file. Don't worry about that. LucasArts games usually don't have that, instead the options are selected by adding perimeters after the .exe file.
For example, If I want to launch the game with general MIDI and Sound blaster support on interrupt 5, type DOTT.EXE R S220/5/8 (for more options just put a ? after DOTT.EXE)

Another thing you can do, instead of typing DOTT.EXE R S220/5/8 every time you want to play the game, is make a batch file that would look like this:
@ECHO OFF
DOTT.EXE R S220/5/8

Then you would just lunch that .BAT file instead.
I hope this guide was helpful as this sight has been very helpful to me.