Second house using xfinity to stream

Yes. That is what I am asking. 

Gotcha. You can access your Xfinity Stream app or web portal while you are away from home, however, there are some channels/movies/shows that can only be viewed while connected to your Xfinity in-home network (your first home) since the entitlements are solely linked to that account. The link will provide a list of what channels are available outside the home network.

How do I access this on my roku? Says I need to be in the home with the TV service to stream 

I gotcha, @user_dymwlh! You would need to change your Primary account to reflect the address you are at now. You can always change it back and forth as needed. You will have access to the channel lineup associated with the address you select as the Primary address. This link shows How to Switch Between Multiple Xfinity Accounts, https://www.xfinity.com/support/articles/switching-between-multiple-accounts. The instructions for this are near the bottom of that link and I will post them below as well.

Your primary account is displayed by default. To change the account selected in these apps, one option is to change your primary account. This can be done online under the Your accounts section located at customer.xfinity.com/#/settings/account/linked-accounts.

From here you can view all your accounts and choose a primary account you want to set as a default across your Xfinity apps (Xfinity, Xfinity Stream, Xfinity Home, etc.) by selecting the Make This Default option.

This should log you into the address you are at now when you use the Roku. Please let us know if this fixes the problem or if you need additional assistance. We are happy to help!