West Papua (Gam, Mokwam) independently?

I am leaving for Sulawesi (Manado) next month. I only have about a month to spend in Indonesia. However, after a few days in North Sulawesi, I would like to fly from Manado to Sorong (and try to get to Pulau Gam for a few days snorkeling) and also to Manokwari and try to hire a guide + transport to stay in Mokwam for a few days birding. I am not planning to bring a tent and cookinggear etc. Just a sleeping mat/bag + mosquito net.
Anyone here ever done this without a travel agency, just arranging things on the spot?
Is 20 days too little time to ‘do’ Raja Ampat and a few days Arfak mountains?
I know that arranging a guide/surat jalan etc will take time, let alone wait for the transport itself but it seems that doing 2 things should be possible. I am just wondering how difficult it is to arrange these things by yourself. Any tips or experiences welcome!

Nice trip, It is possible to arrange these trips by yourself (with the help of a local guide).

See Tips & Trips (in english) above in the Papua Reiscafe (as a sticky message)

Whenever you arrange a trip or tour, I advice you to make sure all the prices and other plans are clear and agreed on with your guide and/or driver.
Make sure you know what is included, what is not included, what you have to bring yourself, how your transport is arranged, etcetera.

If you hire a guide, please make sure that the fee per day for guiding is clear. Also I advice you to do everything with ‘open purses’. By that I mean that you pay cash to the guide at the moment a transaction is
made, for instance: a boat trip, buying groceries, paying for an overnight stay, etc.
Keep in mind that the fee for guiding does not yet include costs for the guide himself, like transportation, meals and drinks and overnight stays. It’s normal that the tourist pays these things too.