Indonesia is a good choice for your wish list. You'll have no problem filling up 30 days.

If you come from a country that needs a visa for Indonesia, you can get a 30 day visa on arrival in Jakarta and Denpasar airports. I'm not sure about Kalimantan. Visas can be extended another 30 days in both places. Be aware that the 30 day visa includes your arrival and departure dates. In Bali it's all right to overstay a few days, but they will charge you for the extra days when you go through immigration. Alternately you can get a visa at the Indonesian embassy or consulate in your home country, but this is a little more complicated.

This is a great source of mountain/volcano information: http://www.gunungbagging.com/

I haven't been to Indonesian Borneo -- just the Malaysian side -- so can't comment on specifics. Kalimantan is less developed; Sabah and Sarawak are still plenty wild and offer better travel facilities. The Miri Caves near Miri in Sarawak are extraordinary.

Bali is a small place, and you can accomplish everything on your list using Ubud as a base. Although Besikih, Tegallalag, Jatiluwih are worth visits, there are temples and rice terraces all over Bali.

There is a big APEC meeting planned for Bali the first week of October, followed in the second week by the Ubud Writers and Readers Festival, so Bali will be very busy at that time. The UWRF is well worth attending, but be aware that accommodations will be in short supply.

In Java you need to plan your transportation carefully as getting from West to Central to East Java can be challenging. Flying is the best way to get from place to place though it may involve some back tracking. I would definitely get a guide for Ujung Kulon and the far west coast. Central Java -- Yogya and Borobudur -- and Bromo you can do independently unless you're planning serious trekking. If you are mountain climbing, go with a guide.

I'm less enthusiastic about the beaches of south Java (though I haven't been to Batu Karas). Lots of good surfing in Bali too.

From Bromo you can continue to Ijen then take the ferry across to North Bali. Pemuteran is the place to stay with access to Menjangan.

I would suggest that you consider adding Sulawesi, either as an addition or instead of Borneo. Tanah Toraja in Central Sulawesi is a profoundly interesting culture, set among fascinating scenery. North Sulawesi has some of the best diving on the planet: Bunaken and Lembeh Strait especially. I like Kungkungan Bay Resort. Tangkoko national park is a good choice for wildlife.

For komodo dragons you have to go to Komodo.

30 days in Indonesia - what a luxury!

Personally, I'd advise skipping Jakarta. We were in central and eastern Java in November. Our trip report might be helpful:
http://www.fodors.com/community/asia/kathies-return-to-jogja.cfm

Travel in Kalimantin (Indonesian Borneo) is difficult. I've been to Sabah and Sarawak and loved them. You may need the assistance of a local agent to work out that portion of the trip.

Have a wonderful trip!

Tulamben is fabulous. The diving there was unforgettable.
http://www.libertydiveresort.com/
If you can get up to Tembok there is wonderful accommodation there. http://www.poincianaresortbali.com/
Flores is worth the diversion. You can see the Komodo dragons on Rinca too. Check out http://kanawaislandresort.com/room/standard.html
We hired a boatman to take us out to Rinca. It was 50% less than organising from Labuan Bajo.
For Jogja check outhttp://bladok.web.id/
I can afford five star accommodation but I prefer the cosy, small, privately owned places where I can get to know locals. Have a wonderful trip!
Happy travels!

hi natashapaterson,

even though i am an Indonesian, I personally not explore Indonesia enough, but maybe there's a few information that i know.

in Banjarmasin, there is 2 floating market. the originally one is in Barito river. but the last time I went there, there is not really many seller and market situations happen in there. but, the plus point, after you visit the floating market, your boat will offer you to go to a "kambang" island. this is a monkey island, you can go enter the island with just approximately 1 USD as the entrance ticket/person.

the other one is in Martapura river. this one is made by government. i never go there, but many of my friends said that the market is more crowded and more "touristy". and i think this one is more suitable for you.

i live in Banjarmasin personally, you can contact me if there's any question about Banjarmasin, i will happily help you.

about diving, you should consider Bunaken. it is in north of Sulawesi.

You might consider spending a week doing a lie-aboard dive cruise from Bali to Komodo and back. The variety of dive sites is amazing, and of course there's time to see dragons and other wild-life on dry land along the way. Of course, you have to be really into diving to sign up for that kind of trip. I can recommend either of the Mermaid boats, or if you want something even nicer, check out the Damai fleet. Flores does have some really interesting places, in addition to Komodo, but the infrastructure isn't quite there enough for me to recommend it.

Another poster mentioned Bunaken, which is also nice, although I prefer the fun of muck diving around Lembeh, personally. Actually, Sulawesi as a whole is really amazing and probably doesn't get enough attention. The landscape and culture of Toraja is truly unique, and in addition to the diving, there's some great landscapes and wildlife around northern Sulawesi as well. It's worth a look.

Hi,just for another alternative, for your trip to Kalimantan, I'll suggest you to spend some time in Derawan, Berau, East Kalimantan. It's the rising diving spot in Indonesia with its remarkable Maratua island ( green turtles colony, dolphin, barracuda) and its pre-historic jelly fish lake, Kakaban Lake (only two in the world; in Palau and in Derawan. However, as it's still very natural, the infrastructure are not well-established although flights, water transports, resorts and cheap hotels can be easily found there,the trip is quite time-consuming and you can't expect it to be tourist-ready as Bunaken or Bali. Please check this website for more info in how to get there and what to expect there http://penyu.nl/berau-information/how-to-get-there/