Yes, if you want to make a new trail or do anything that requires the much earth movement you will hit a NEPA snag. But as far as trail maintenance or minor improvements/fixes most programs will have existing programatic NEPA in place so there would should be no problem. However, this can vary from office to office. In any case, the person on the ground wouldn't need to be concerned with getting the NEPA done themselves. As you go around and talk to resource professionals about potential ideas, be sure to ask if any of the potential work you might do would have any NEPA needs. If so there would likely be a timeline involved that would not be compatible with yours.
A NEPA nerd