Hey, Im new here too and had the same trouble that you are having and after a lot of trial and error i figured it out. So here is what i did.
Step 1: Dwonload TLR 2.0 from here
http://games.on.net/file/13849/The_Long_Road_Medieval_2_Total_War_Mod__Client_v2.0.0
Step 2: Download TLR 2.3 from here
http://www.twcenter.net/forums/downloads.php?do=file&id=2649
Step 3: Download TLR 2.3.3c patch from here
http://www.twcenter.net/forums/downloads.php?do=file&id=2651
Step 4: Install TLR 2.0 with installer
Step 5: Now go to "The_Long_Road" folder in your M2TW folder and rename the "data" folder inside to anything else. Then put your TLR 2.3 data folder in "The_Long_Road" folder.
Setp 6: Copy & Paste the 2.3.3c patch data folder into "The_Long_Road" folder and overwrite anything it asks about.
Step 7: Start M2TW just like normal and select The Long Road from the menu.
Note: when you put the 2.3 data folder into "The_Long_Road" folder make sure to rename the origanal data folder first this in my time playing the game helps to get rid of a bug that causes the game to crash every few turns. It doesnt totaly go away but it akes it happen like every 8-9 turns instead of 1-2
So thats what i did, it seems a little complicated and i may have put a couple extra steps in there but it works and is a danm fun mod. Anyways I hope you enjoy it.
Peace, crazymonky123.
Edit: if you have the steam version like I do make sure to put the corect install path in the 2.0 installer.