Roo does currently support remoting via JMS. So one option is to create a complete application (including front-end) for the first box and then create a JMS listener to listen for object requests from your second application.
The relevant commands for JMS are as follows:
I have written a blog article a while back which shows JMS usage with Roo:
install jms -provider ACTIVEMQ_IN_MEMORY
new java jms listener -class com.foo.MyListener
add field jms template -class com.foo.MyService
Hope this gets you started.