Looks like the 4200 has an Atom D525 processor. Intel's Ark says that processor's memory controller supports 4 GB of RAM. A bunch of people have confirmed it works with 8 GB, but you have to be careful about the chip capacity. 4 GB sticks made up of 16 chips at 256 MB each apparently work, but 4 GB sticks made up of eight 512 MB chips apparently don't.
Distributed is definitely the way to go if you can. R80+ management is heavily processor-bound. Management on a 4200 will not perform well due to having only two cores.