The study material of the 'basic-program' provided by the FPMT covers a great deal, but (1) what it covers also depends on the teachings and commentaries you follow (2) and it is a specific traditions and a specific college. You will learn there are various traditions, and various college that propound different point of views. Once you are familiar with one and firm you will understand the other better as well. You can read the study material - root-text, recommended books, transcripts of past BP - but you would not get that much out of it. You would definitely get more by attending a BP, either online or residential. I advise you not to just study on your own. Receiving teachings from a qualified teacher is of utmost importance.
The BP is done in 2 years in some centers, 3 in others, 5 yet in others. Because of this, the transcript of the course given by Geshe Chonyi on buddha nature (with Maitreya's root-text) is relatively short and easy and he quotes Gyaltsab Je's complicated commentary once or twice. Geshe Gyaltsen's transcript, on the other hand, is long and it is a word-by-word Gyaltsabe Je's "oral" commentary that he gave over three months. I know because I attended as interpreter from English to French.
Some study Gyaltsab Je's commentaries while others do not (precisely because it's terse, dry, and not intended for beginners).
The BP is great. You would learn about Lam Rim (mainly Tsongkhapa's), Tenets (doctrinal classifications), Lorig (epistemology), Buddha nature according to the meaning of the Prajnaparamita but also the third turning, etc. It might have sectarian aspects but these are not avoidable. This is because the FPMT is spiritual, or "religious", although it is academic, it is not oriented towards inter-textuality too much, or historical perspectives. Comparisons (as are done in the context of Tenets) always have an agenda. Still, if you are a practitioner, at some point you will have to dive in a water that you will have come to see as - if not the absolute truth - beneficial, wholesome and functional and aimed to your goal, enlightenment.