How are your ways to find good locations, if you go to a region where you have never before?
For myself, I use Google Earth and hiking guide books to get to know the region and find paths with interesting flora. In hiking guide books often are informations if the paths are crowded or not and about the flora.
In the field I often use the Google Earth App on the iPhone when I have to decide in which direction I should go.
Have done this a lot since Lepidoptera became a main interest in 1964. The more you know and do it the easier it gets. The correct habitat and elevation for the species being sought, with preferred larval food plants present, the habits of the species, when they would be on the wing or livestock present there, etc are starting points. Not too hard to find out where the correct habitats are before even going to a new place or country now days with the Internet. That doesn't mean a species will be there though. But its also not hard with the Internet to locate local Lepidopterists' almost any place worldwide, or those that specialize in certain families/genera, and they can be a great source of glory holes in many places to plan on visiting if they will share them. And don't forget local plant biologists who will know exactly where the plants are.
Books are fine as far as they go to obtain specific site data, if the data is correct. Lots of books have some wrong sp/ssp identifications, wrong ranges, wrong plant associations, etc that get passed on from book to book. Add that many serious Lepidopterists' don't publish exact species location data either. Done that myself to protect rare species from the hoards that would decimate them at a location if their location was given (have seen localized populations completely wiped out from this exact practice). Better would be papers written about specific locations or species.
Google Earth, topo maps, books, etc may be a way, but if I am going the high expense to travel to a new place for Lepidoptera I want far more ahead of time than what it can get just from them. FWIW
I do refur to Google earth. Hicking books tipcaly cover state or national parks that you can not collect in. Sadly there are no books I know of that cover off the beeten track hicking trails that you should not be on or are on private property. You just have to roam all over the country side and hope you find a good spot. After a favorit collecting site of mine became part of a state park I was at a mager dead end in my collecting! The place had at least 12 to 14 species of butterflies to be seen through the spring and summer. The most in any one spot in the county I live in. The county parks were the only other places I could still collect. One park put in a frisby gulf cores that destroided the populations of Spring Azures, Red Admirals, Satyr Commas, Acmon Blues when weedy areas were cut down. These butterflies are now much less common in the park. Another park is putting in some kind of water pipe pump building - this will have an impact on the Buckeye Butterfly population as well as other speacies at the park. The other parks offer a very small number of leps. I studyed the maps trying to find a new place to catch leps. I did but it offers just a small fraction of the species I saw at my favorit spot. It is also a far drive from home into the mountains - so I do not go often. Another spot in the mountains in the sand hills has Checkrspots by the hundreds. Will be going there to collect larva in April. I must keep serching maps, keep talking to folks to learn about better lep places. Folks can be realy nice and help you learn of a new spot. That is how I learned about the Checkerspot location. I can only hope some one who ownes lots of undisturbed land with trails will let me hike and collect there some day. But till then I will make the most of my new spots in the mountains at butterfly time.