Your best option would be to setup HSRP is possible. That way you have a Hot Swap IP address on both routers so you have a single address to point to no matter which is active. As follows:ROUTER Ainterface FastEthernet5/1/0 ip address 10.x.x.200 2...
Your problem is EIGRP, EIGRP has a weight of 90 so when your static route is down EIGRP takes control. You need to reduce the weight from 200 to 50 and it should work.
EIGRP has a general maximum of 400 adjancentcies. I have had networks up to around 600 adjancentcies, but if you have multible core routers; more than 400 will cause the network to flap if a router goes down.