There is a reason why it is isolated. The appropriate option would be to configure an additional NIC or 2 in the hosts that you want to access the storage on the isolated network.
Outside of going to that extreme, yes, you should be able to reconfigure the networking to work in an existing production environment... but you need to take into consideration the reasons why it is isolated.
Storage based traffic over IP is somewhat different than standard IP based traffic and requires certain settings to be efficient. If you are simply looking for quick and easy storage access and don't care about performance... have at it. Change the IP's, rconnect to the LAN.... configure your iSCSI initiators and present storage.