Welcome to the forums.
I too have the three Titan sets but I also purchased Mars Station, First Light, and Celestus Pravatis. The last three are non-TLX but many of the props work great and flesh out a build nicely. Also the skins form the sets can be used with gimp to work into a TLX fashion. I took the Mars dirt tiles and made TLX tiles now for my planet side outdoor encounters. Combining them with Hinterland Forests and Cliffs really bring a build together. I will generally build a 2'x2' area with 4 levels. The combination of all the sets can really allow for great game play and player immersion.
As stated in another thread if I am not mistaken some of the Vaulted sets will also become TLX based and classic will stand as they are and have no plans to become TLX based. I could be wrong about that but I think I read that in a thread about the Vault and Classic classification of the Models.
Some thing else I would suggest to help with planning build outs is the TLX Planner. I really like mine and at only $5.00 it is a nice tool to have on hand. I will also push out a png form the planner and use it as a map for the players. Of course you may already have purchased it.
Anyways Welcome!
-D²