The wiki is still up, so a lot of your questions can probably be answered by sifting through there. http://wiki.crymod.com/index.php/Main_Page
For the terrain detail texture, you can change it's view distance by going into the 'Terrain' tab in the rollup bar > 'Environment' > 'Terrain' > 'DetailViewDistRatio'.
For objects, just click on your brush or entity and in properties window in the rollup bar, change the 'ViewDistRatio' number.
Also, the above problem you're having could have to do with (and I'm guessing it is) various terrain texture bugs in the editor.
It may be a simple matter of going to 'Tools' > 'Reload Textures/Shaders' as well as 'Reload Terrain'. Or, you may need to regenerate your terrain textures, export to engine, save, close the editor and reload your map.