Yes, but, like most "rural" bus routes in France, the service is very sparse largely providing a service to Metz for school pupils and (to a lesser extent) workers. The timetable can be found here www.infotim57.fr/fr/fiches-horaires.html by selecting line 73 and noting carefully the days of operation of each service, there is a list of the periods when scolaire/vacance services apply elsewhere on the page.
The area isn't, in fact, at all rural being a rather messy string of dormitory villages (with some low-key industry) running either side of the Meuse - a lot of the population probably works in the GDL these days. It is possible that the other side of the Meuse might be more accessible, the nearest bus stops there look to be about 2 km from Bousse, the nearest rail station rather further, but I haven't investigated further.
Thanks very much. I guess maybe I can do without seeing Bousse as it doesn't sound that appealing!
It is fairly comprehensively covered on Google streetview so you satisfy your curiosity without actually having to travel there.
Sounds good. I was thinking there probably wouldn't me much left form when my ancestors lived there anyway (1760s) so I wanted the bus to get an idea of the milieu. But I'll check GoogleEarth. (Otherwise I'd have to try to fit in three bus trips---to Ars sur Moselle, St-Privat-la-Montagne, and Bousse in one day. Doable but quite complicated!) Thanks again.