Balgo to Yuendumu is the longest distance between fuel(560 km), However Balgo is 33 km off the Tanami Trk.Balgo as an amazing gallery there if its open. We timed our trip to visit it, however you will need very deep pockets to purchase anything there( thousand/s) as it is of the very highest quality.
Billiluna to Yuendumu is (576 km) and 49 km closer to Halls creek than Balgo, and is only about 1km off the track.
Last year we travelled from Alice (home) to the Kimberley this way, in a Pathfinder with a swag on the roof. Part of our planning was calling ahead to Yuendumu and Balgo to check that a) they had fuel, b) they were open on the days we were traveling through.
The road is mostly sealed to Yuendumu, and then often graded, through into WA, I cant quite remember where its sealed again. It was far better than we imagined, about 140 km of rougher stuff, then we met the graders and while I'm a very conservative driver I was happy to sit on 90 mostly. HOWEVER we met some people who traveled it a day after us in a Izuzu 4WD truck come bus and they had nasty things to say, damaged their suspension.
We did try to stop to smell the desert roses, camped close to Mt Tanami by the side of the road, and then camped at stretch lagoon near billiluna. My wife was too scared to camp at Wolfe creek crator (even though she has never seen the movie) however it was an excellent detour and walk there, and great looking campground.