I have a similar layout with two track parallel main with loops at each end. It is standard DC, with two independent walkaround mainline throttles, segregated in to four blocks. Each block has DPDT switches on each track to allow changing throttles to perform switching to sidings along the mainline line.
I tried the AR initially, but found the simplest approach was to wire the loops to independent power packs. If I want I can run up to six trains in the same direction, continuously around the layout, depending on the length. Of course you can't perfectly match the speed between sections, but this is not really an issue since due to slight differences in voltage drop due to varied wiring arrangements from block to block, there is always some slight variation in speed as a loco travels from block to block. And of course the ability to do this with DC also depends on the motors characteristics. There are some locos that simply run too fast (Atlas RS-3 is most notable) to operate in this manner as even at slow speeds they can over run into an occupied block. The operating strategy seems to work best with no more than 3 trains.