How to convert primary keys into clustered primary keys for a great number of tables keeping referential identity
Your approach is correct and pretty much the only way, but I would consider using a tool like Red Gate to help me.


drop all FKs without scripting them
change the indexes (as above)
generate an "FK only" script using the compare tool to re-apply the FKs


The 3rd step saves writing something to script our your FK definitions, or fiddling with SSMS/SMO