Did I get it right, you're using the drops from Deep Forest Road as xp fodder? If so, that is horribly inefficient because they are low level. You're supposed to use higher level fodder from maps like Return to Ruins, Remnant Vanquish 3 etc. Deep Forest Road is a good way to get gold, but you're supposed to sell the units you get from it, not feed them. Check out http://harem-battle.club/millennium-...questions.html "Where do I farm for things I need outside of silver units?" for more details.

Other than that, Monday daily is your best friend. Even if you can't do H yet, N still gives a fair bit of gold.