I usually texture in Lightwave -- mostly image maps or simple diffuse colors . I use Seamless Texture Generator Pro quite a bit for things like stucco, metals, flooring, etc. to make them seamless. And then Shadermap 2 to make the specular, normal, and displacement maps. I apply these in Lightwave.
Then I use the free Poseray program to import the Lightwave model. Poseray is great for checking/correcting geometry and gathering all the texture maps. Then I export it as a package into a Terragen "data" folder (this is the .obj and .jpg texture maps.) So I have all my originals in my Lightwave content directory and my new obj and copies of the texture maps in my Terragen folder. Poseray has the option to limit (convert) the size of the texture maps to say 512 pixels (many times it makes no sense to use high resolution maps on objects that won't render very large, and a good seamless map can look just as good at a lower resolution.)
On thing nice about lightwave is, if you build a model that's 10 meters tall, it will import into Terragen and be 10 meters tall. If you build it to set on the zero point (y axis) in Lightwave, it will import to the zero point (y axis) in Terragen. The x and z axis match too. This allows you to build an object at a certain x/y/z in Lightwave, then build another object at a specific spot relative to the first object, and then import each separately into Terragen and the positions are maintained. Hope that makes sense.