I in general don’t like stratigies like this, the are dependent on the opponent not looking carefully your options and missplays. The assume your opponent plays wrong, these plans are usually fairly easily countered,
As russia I would place my stack of unit in bryansk awaiting the attack once I see the factory in rumania, of the beginning units, 7 inf, 2 art, 2 mechs + 2 tanks within reach would be placed there (or within range of rostov),
When russia see a factory in rumania, he would probably build either 11 inf + art or 3 inf + 7 art in ukraine and moscow., on R2, after seeing the 10 trannies, the natural place to place this stack would be in rostov, and building 3 infs in ukraine, 3 arts in stalingrad (or inf if art was built on the first turn) and 4 arts in moscow (or 4 mechs or 1 tank 1 ftr, or 1 bomber 1 mech)
so when you are landing in cauc in G3, the russian counterattack on you will be between (best case) 18 inf, 6 art, 2 mechs, 3 tanks, 2 ftrs and 1 tac, worst case it will be 13 inf 9 art, 2 tanks, 3 ftrs 1 tac.
in both cases the stack that lands in cauc is killed instantly, you have a maximum of 20 land + 4 italian ftrs, and win 32%- 23% chance of winning of the combats (in the best cases, assuming ussr built no planes and you move 10 inf + 10 tanks, which you dont have), cripleing your entire army and losing your game right there. leaving you with an average of 1 italian fighter after the combat
This plan is dead if the russian plays as defensive as possible, this is how I would play the russians against a factory in rumania, and this is how I would respond to the