Don't worry.Do you know how to shoot mapshots?I have a way to recover it.Just follow the steps.
1. shoot mapshots of all the routes/cities you've made.
2. take another FR rom
3. remap (gah) two maps,looking at the mapshots.
4. make an ips file,then continue making two maps,and make again ips file.
That way,the rom won't crash.