Lessons learned

update: food and drink, rocks in your rice.

Visa
Pay to have it done, otherwise it is a bit time consuming and tricky.

Communication
Most people know enough English that you can probably muddle through so long as you are very patient and don't mind when you don't get what you expected.

Unlike India or China here the facial expressions, tone of voice, and body language is as we expect in the West.

All the folks we dealt with were extremely friendly.  During our 3-month journey we ran into some grumpy fundamentalists on a very few occasions and had no interaction with them at all.  Maybe just as well.

Learn to speak some Indonesian for the locals will appreciate that you want to try, at least yes, no, thank you, please, good morning, good night,...

Money
There are ATM's everywhere that will accept Visa and MasterCard, with English menu systems.  Look for those that issue 100k Rupiah notes, and withdraw the maximum, usually 200M, to reduce the cost of getting money.  We usually do two withdrawals of 200M, around $400USD, at a shot.  In Sarangan we had to take a taxi ride for a 10 minute ride to get to and ATM with small bills, but this situation is the only one we ran into where there was not an ATM within walking distance.

Carry some change in your pocket to give to street beggars in the small towns.  The locals do this too.

Expect to pay a bit more for stuff sometimes simply because you are a foreigner, but really you can afford it, and these folks can certainly use it.

Expenses in Indonesia will likely run 2 times your plan.  I'm pretty sure ours has.  Too much fun.

Accommodations
We avoided hotels catering to Westerners because they are so expensive, and more likely to get bombed.  The best deals are Homestays for in the neighborhood of $20USD/night or less including breakfast.  Don't expect everything to be fully operational.  Maybe the toilet won't flush right or there's a leaky sink drain, or the breakfast could have been better.  3 and 4-star hotels charge US rates room, food, and drink.  Book them online when possible.  Agoda (owned by Priceline) works well for this.
You can actually come into town with no reservations and have a cab driver take you around.  I took this approach in Bali.  There are at least 10 times the number of hotels than show up on the web.

Hygiene
Wash cloths do not exist.  Bring your own.  We bought a dust cloth at an Indomaret (local convenience chain) - works great.
Toilet paper is unlikely in public toilets.  Bring your own.
Napkins may not be available in restaurants.  Bring your own.
We carry a packet of tissues, always.
Laundry can usually be handled by the hotel/homestay.

Food and Drink
Bottled water is available everywhere, in little streetside stalls, everywhere.  Ice is made from bottles water, and everyone is aware we don't drink anything other than bottled or boiled water.

We still do not eat fresh vegetables, only cooked, just 'cause we're chicken.  I take it back, we did eat some tomato slices at a place in Yogya owned and run by an Ausie.

Almost forgot, Indonesians generally eat with a spoon in the right hand and a fork in the left, picking at their food, examining it, deciding what piece to take next.  They are also looking for foreign matter.  Occasionally you will find a small rock in your rice.  Look and chew carefully.  During our 3 month stay I can recall maybe 2 or 3 instances for each of us.  Oh, I broke a tooth in Guam on some chicken sate that I killed on the grill at my sister's place. I got the tooth fixed in Madiun, Indonesia.  Found the dentist on Facebook, he used an amalgamation cured with UV light, refused to be paid, and gave me a T-shirt his father sells.  I did end up giving him what he admitted was his usual fee, something a little over 10 bucks.

Alcoholic beverages on Java are almost exclusively limited to beer.  Arak, a local rice wine home brew, can be had under the table.  Yogya had some real box and bottle wine.  Bali has some wine.

Insects
Bring your favorite bug repellent, or buy some, available in streetside "drug stores"  (Toko Obat / Apotik).  Mosquitoes don't like me so much, but they love Pat.  Romantic outdoor bathrooms are beautiful, but really!

Everything Else
will work out some how or other.