Question

Hello Rabbi. I’m on the Daf Yomi track. We started about 5 years ago, and we’ll finish in a little under two more years.
At some point this year I reached the conclusion that I do want to finish the track, but definitely not start it over again. You can’t study a page in a deep and serious way in less than an hour. It’s nice the first time around to get some concepts and some basic Talmudic thinking. Also, there are pages that don’t have much logical or halakhic value, if any at all, and maybe it would be better to focus on the ones that do.
So I’d like to ask the Rabbi’s recommendation: which Talmudic tractate should I start learning in depth, and in what way should I learn it (medieval authorities, later authorities, etc.)? True, there are still two years left, but I don’t expect to switch from breadth study to in-depth analysis in a single day, so I’d like to start trying fairly soon to combine the two. I’d also be happy to hear the Rabbi’s recommendations for study aids, if there are any. 
And maybe this is a separate question, but I’ll put it in here anyway: how can one derive Jewish law from the Talmud and the medieval authorities? There’s always this split: you study the Talmud in depth, and then afterward you close it, take off the hat, and study the Mishnah Berurah to know what to do.