Played all day yesterday. All I managed to do was get one more ending and then waste 14 hours accomplishing nothing at all.
The two Rank +5 bonuses seem the best to take at the start since every 10 rank stats get a boost and cards all add this bonus to the leader of their area.
I tried doing a short quest in each area which put two Chaos swords there for a turn and helps slow take over. I tried killing the easiest of the 3 apparent bosses in each area then the next hardest. I tried doing only one area. One area gets conquered and end boss shows up to kill you in 2 hits every time. Except one which had me wait out in JAPAN for a bit first.
I had trouble killing a giant boss in Helman that gives game over suddenly at either low hp or after too many hits. I'm not sure but Rance LV45 which you get from moster girl H scene when you're picking at the castle seems to work on it. It's also lets you catch monster girls. I prefer using Sil LV43 which boosts Rance and having his other card with 0 cost attack; nice 2 ap combo. Rick lv 58 has two free attacks you can alternate and Aegis has a free ranged and a strong one use attack.
Also realized you can save someone from an area when it is just about to be taken over.
Going to try two areas and maybe saving the person from the others.