Fly fishing for bass, whether largemouth,  smallmouth or others is a whole different deal than fishing for trout. First, and most importantly, bass are way more aggressive than are trout. Second, locating bass is usually way less complicated than finding trout...unless of course the trout are rising. The key to finding bass is structure. Bass are primarily ambush predators and, as such, almost always look for cover from which they can attack unwary prey. Weeds, rocks, sunken logs are all examples of where you will likely find bass. Third, if you bring your trout fly box(es) on a bass trip, there is a very good chance that everything you have is too small. Bass flies are large...very large when compared to trout flies. Bass tend to prefer big food over small food. Therefore, your gear needs to be bigger and heavier so you can adequately cast these big flies that typically have more weight and, being larger, have way more wind resistance. Finally, compared to trout, bass are everywhere...they are a "warm" water fish so do not require the cold flowing water that is typical for trout.