I like the way it is set up now. If anyone should complain about leveling it is me

You should go to the next city and fight the mobs there. They will be strong enough for you to level.
Another thing to do is when you know you are close to becoming too strong for an area, stop spending your SRP. That way, you will be strong enough to kill everything, but weak enough to gain the full amount of SRP. Hoard it until you have enough to bump yourself up 20 levels or so then move on.
The mobs around Endlesberg were close to becoming too weak for Fig when he was at around 125 all round stats. So, I stopped spending SRP and continued to explore. After a couple of days I had accumulated roughly 30k SRP (with full proficiency). This was enough to bump him up 100 levels (20 in each stat). Now he is around the 140 in all stat mark, there is nothing made yet to kill. So, I work him and start on a new monster. Working still gains stats and he will still grow through evolution.
Your monster is still able to accumulate full SRP from the mobs around Endlesberg. The reason you are having difficulty with the God is because you are putting all of your focus into a single monster. This is fine, I killed all bar Keira with one monster, but if you had another strongish monster along side of "Princess Belle" you wouldn't be having this drama. They are Gods... they are meant to be difficult to kill.