There are many Westerners married to people from Bukit Lawang. In most cases the Indonesian people are former guides.
In the event of marriage, it is normal in Indonesia to have a large wedding party for many people in the village. Attendance may number in the hundreds. The cost of such a wedding is variable, but generally you will buy one cow (sometimes two - costing 10 million rupiah each), plus other food and entertainment. The total cost for such a wedding may be around 30 million rupiah.
The wedding party is separate from the legal marriage, which under Indonesian law must be between two people of the same religion. This means the Westerner, to perform a legal marriage in Indonesia may be required to (at least nominally) convert to Islam. To avoid this, a wedding performed outside Indonesia (which in Western countries does not require you to change religion) is also valid in Indonesia, but the marriage must be reported to the Indonesian authorities within six months of marriage.
Children of the marriage are entitled to dual citizenship, however on becoming an adult they must choose between Indonesian and foreign citizenship - dual citizenship in Indonesia is otherwise not permitted, and those taking a foreign nationality automatically lose their Indonesian nationality.
After marrying an Indonesian citizen you acquire rights to live and work in Indonesia. In particular, your spouse can sponsor a KITAS, or temporary stay permit. This entitles you stay in Indonesia for a year. A KITAS can be converted into a KITAP, or permanent stay permit, entitling a stay of five years. A KITAS/KITAP is accompanied by an IMK, or re-entry permit, which allows you to re-enter Indonesia without losing your KITAS or KITAP. A KITAS IMK has the same validity as the KITAS (1 year), and a KITAP IMK lasts for two years. Work on a spouse KITAS or KITAP is only for your own business - you cannot work for others without a work permit. A KITAS costs 800,000 rupiah, plus 1 million for the 1 year IMK. A KITAP costs 3.5 million, plus 1.75 million for the 2 year IMK.