Nowadays with planes, english-speaker guides, vaccines and anti-malarial pills, it is far safer to go there than during Meek & Wallace's times.
Still, some advices must be given for all of us who want to see live Ornithoptera and Delias.
The author in West Papua, August 2009
If Papuans don't cut insect collector's head anymore, Indonesian authorities can send you to jail for killing one common Eurema (while those authorities have destroyed the whole Borneo...).
So be sure to check if a collecting and an export permit is needed where you plan to go.
This website is very well done to check this : http://www.theskepticalmoth.com/collecting-permits/
If you need to apply for a permit, find an association or a museum that can help you and apply at least one year in advance. It's boring but you will feel far better with all official papers.
. The net : once in a jungle, you will discover that Morpho, Agrias and Delias do not fly at the same level than our paleartic leps... they prefer flying at 4 or 5 meters high, so yes bring a very long net !
The good tip is to bring 3 or 4 nets, 2 for you in case you break one, 2 for your local guides that will be happy to help you.
. The shoes : you need good trecking shoes to avoid dangerous fall + plastic sandals to cross streams. Some collectors use plastic boots, it's heavy but is efficient to avoid leeches.
. The GPS : very useful for your data. Because sometimes you are in a place that nobody knows and every local you meet will give you a different locality name...
. The medecines : don't forget all your medecines... once in the jungle in the middle of nowhere, you won't find a pharmacist easily.
Entomological local guides is the key to make successful collecting trips. They will avoid you many problems with local army/police/village chiefs and will bring you directly to good collecting spots. Without them you will spend your 2 weeks in Sulawesi trying to find a virgin patch of forest.
I can advice you some guides for many destinations if you need.
Always be polite with locals even if they don't understand what you do. If they refuse you to collect in their land, even if you have an official permit, don't do it.
Your Indonesian LIPI permits has no value for an Irian Jaya village chief, you also need an authorisation from him... that's why a local guide is very useful.
Always try to learn few words of local language, it helps a lot.
Do not collect in crowdy area, many people will come to bother you.
This said, you will see that people in those countries are really nicer with insect collectors than Europeans or Americans.
Terrible roads, dangerous slippy paths, leeches and snakes, hostile villagers, collecting in tropical areas can be dangerous... but that's also why you wanna go there !
Larsen's book about the Hazard of Butterfly Collecting is very funny about this subject.
And of course for those who cannot travel to the tropics, you can still find some rare insects on Collector's Secret : http://www.collector-secret.com/index.php/top-auctions/
Here are my main advice ! Please share yours !