I planed to do this crossing but due to a change of plans and a bit tried of the palmtrees landscapes and tabacco I changed plans.
In any case, I leave my advice here in case any adventurer wants to try the challenge.
Here it says you can go out Indonesia through that border, specially if you got the visa.
Look at the land border crossing Nanga Badau.
Here it says you can cross that border to enter Malaysia
I don’t know why it’s a sabah webpage but it says that the Lubok Antu border is open, so with the visa free malaysia for most of western countries it shall be fine.
It’s doable, even knowing only few words in Indonesian. At least there are busses all the way to Putussibau, although I been traveling by hitchhike. The road conditions go from good to horrendous, although any traveler willing to go there probably is familyar with that. In any case it’s better to take it slow to enjoy the experience. The experience means, according to my previous ones, a lot of good friendly attention, a lot of free sugary drinks and fried food, palmtrees, invitations to peoples houses, tobacco, and many nice surprises. It’s worth any effort put into it for sure.
People is gonna be extremely happy to see you, so you need to set time to hang out with them and let things happen. Also it’s good to have the time to go to see interesting things that might be along the way or might be off way but worth the time to go there. Specially if invited by a locals 😀
Don’t expect, as you shall know, predictable schedules, good roads (specially in rainy season), comfort, English, other travelers, a lot of traffic easily to hitchhike. But expect to be piked up eventually. They don’t know what hitchhiking is but if they stop, with time and patience and mimics you get to your destination. Get the names of where to go though!
Then seeing the map I would think that there shall be a shortcut that does not go thorough Putussibau but I haven’t found any map showing any roads … That doesn’t mean that they don’t exist, so if you are confident on your Indonesian ask for them.
All the best and good luck!