This screams to me - Warehouse city- with lots of traps n abatis on ur walls and some ATs for the actual damage (closed gates defence).
As suggested above, keep your army size manageable so that even if he plunders you, the stock remaining in ur warehouses can keep army alive overnight. I'd go with just bally n trasports as bulk of the troops with some scouts.
Now, u pad up on stone and gold. U need LOTS of stone to protect ur gold supply (for heroes) and lots of both to limit how much of ur lumber/iron/food can be taken.

Now, to sabotage his perfectionist plans.
Take any empty flats u see around him n NPC them at their current level (lv6s, 1s etc rock ). Destroy his ability to grow that 10 field without using teleports.
Take his valleys with scout attacks every night that he plunders u. It will hurt his farming to not make back enough lumber/iron cuz his production bonus keeps getting downsized.

Making a new lv10 field is risky business. You can either **** off everybody around you and deal with it, or you can allow for ur venture to be slightly less than perfect. Well, ur new neighbour sounds like a perfectionist bully. Have fun taunting/troubling him/her