Since I used the Forum extensively here is my report on the trip. We took the overnight train from Brasov to Baia Mare and everything went smoothly. We paid for a two person sleeper which was relatively new, quite clean and comfortable (newer than the car we took from Budapest to Brasov). Based on those two train rides, it seems Romanian trains no longer include meal service - at least neither of our trains did. That seems strange given the length of the trips, but that is what we found.
We were only spending two nights in Maramures and I was convinced we would see and do a lot more with a guide, so we arranged to be met at the train station by Karin Lachner who calls herself Journey to Transylvania (firstname.lastname@example.org). I arranged the trip with little lead time and all the highest rated guides were previously booked as were the people they referred me to. So I found Karin on the Romanian travel website. She replied promptly and provided a very nice proposal and itinerary, so we went with her. Great choice! She is passionate about Maramures and Transylvania, a native of Baia Mare, speaks excellent English and kept us very busy. We loved most of the big sights (the train ride being our least favorite), but loved even more all the houses we were invited into, the people we met, the crafts and foods we saw and sampled. As far as specific sights, it is hard to pick one best, though the painted churches are breathtaking and the Memorial Museum heartrendingly depressing - won't forget either.
We stayed in Breb for one night, based on suggestions here, and in Baia Mare the second night so we could catch the 630am bus to Budapest the next morning. The bus was small, packed and very slow, so the equally slow train is a better (more comfortable) choice IMO, but there is no direct train from either Sighetu or Baia Mare to Budapest so that option would have taken forever. The only thing I would do differently is to contact a guide sooner in the process and let him or her plan where we stay rather than do it myself as Karin suggested there were some other places we might have stayed rather than the ones we chose based on comments here. And we found Karin's advice and guidance to be uniformly excellent A great visit, if perhaps a day or so too short. Karin kept us going from morning to evening and if we had an extra day or so we might have just wandered, stopped, experienced Marmures in a more quiet way.
Thanks to all for sharing your experiences and helping us have such a great time.